Scientists Discover the First-Ever Contagious Cancer in Fish
It's only the fourth known contagious cancer found in animals, but others may remain undetected.
A mysterious cluster of blackened skin lesions affecting catfish in New England turned out to have a stranger cause than anyone would have predicted: a contagious form of cancer.
Researchers in Vermont studied melanoma tumors collected from brown bullhead catfish (Ameiurus nebulosus) living in Lake Memphremagog. The tumors on different fish were genetically much more similar to each other than their hosts, they found, strongly pointing to the cancer’s infectious origin. It’s only the fourth ever kind of transmissible cancer discovered in animals, and there remain many questions about this cancer and others like it, the researchers say.
“Transmissible cancers are a puzzling biological phenomenon that are not expected to exist,” the researchers wrote in their paper, published Wednesday in Nature, “with the potential to devastate host populations.”
Blackened catfish
Lake Memphremagog is a freshwater lake that stretches from Quebec, Canada, to Vermont. Since 2012, both local biologists and fishers have been spotting an increasing number of brown bullhead catfish with blackened skin in the lake. Surveys have indicated that by 2014, roughly a third of catfish in the area had these lesions.
Though scientists initially suspected the lesions were directly caused by a virus or environmental toxin, it became evident that they were actually melanoma tumors. This only raised more questions since these catfish, like most species, are bottom dwellers unlikely to get much ultraviolet radiation exposure from the Sun (in humans, UV exposure is responsible for the vast majority of cases). The growing and high rates of cancer also indicated that something out of the ordinary was going on.
The researchers decided to genetically analyze tumors from affected fish and compare them to healthy tissue from the fish as well as other unaffected catfish. They expected to find mutations that might explain why these cells were more prone to becoming cancerous. Instead, they found evidence the tumors were very genetically different from their hosts; this then prompted a deeper whole-genome sequencing of the tumors.
Ultimately, they uncovered hundreds of thousands of genetic variants shared between the tumors that weren’t found in the fish hosts or other catfish, well beyond the sort of similarity you might get from a conventional type of cancer.
“When you look at shared variants in non-transmissible cancers, you see many random variants, and as you compare more and more cancers, they share fewer and fewer variants,” co-lead researcher Julie Dragon, an associate professor of microbiology and molecular genetics at the University of Vermont, told Gizmodo. “In the case of transmissible cancers, it is the opposite. The more you sample, the more shared variants you find.”
The researchers did investigate other possibilities, such as the introduction of toxins to the lake from a nearby landfill. But affected fish are widely distributed throughout the lake, and water quality tests haven’t revealed anything unusual. More recently, the researchers have also found this cancer among catfish populations in other ponds and lakes across New England, including places with no major human-made sources of pollutants. So, barring any huge surprises, the only plausible explanation is that this particular lineage of cancer has shifted into a parasite-like entity, one that has long outlived its original catfish host and now spreads to others like an infectious disease.
The mysteries of transmissible cancers
To date, transmissible cancers have been found in dogs, Tasmanian devils, and at least 10 different species of bivalve mollusks, including clams and mussels. This is the first ever documented in any fish and the first ever found in a freshwater animal.
There are plenty of unresolved mysteries about this cancer. Though it doesn’t pose any danger to humans, for instance, it’s still unclear how it might affect the long-term population health of brown bullhead catfish. Outbreaks of some transmissible tumors, like the one found in Tasmanian devils, have a fatality rate of 90%, yet transmissible venereal tumor in dogs is rarely fatal and highly curable.
We also don’t know how it transmits between the animals. Since these cancers have only been found in sexually mature catfish, it may primarily spread when the fish huddle close together during the spawning season. Yet it’s also possible these cells can survive long enough in lake bottoms to be caught by other fish (something similar happens with transmissible cancers in bivalves). And the environment might still play a role in fueling its spread; the researchers note these tumors tend to have high levels of arsenic, a well-known carcinogen. So toxins like arsenic or the hormonal changes of the spawning season might be making these fish more vulnerable to the cancer.
“A big [question] is how the cancer is avoiding the fish’s immune system. We will be exploring that for sure because it can tell us something about how cancers avoid the immune systems in humans as well,” Dragon said.
Another mystery to solve is when this cancer first split off from its original host. The researchers note that the first scientific reports of melanoma in brown bullhead catfish date back to the early 20th century, but naturalist and essayist Henry David Thoreau wrote about similar-looking fish in his home state of Massachusetts even earlier than that in the mid-1800s.
On a broader level, it’s likely there are even more transmissible cancers out there that have yet to be discovered, the researchers argue, and that their impact on the world is greater than we know.
“We think that these may be more widespread, but we are just not noticing them. You often don’t see things you are not looking for intentionally,” Dragon said.
The researchers next plan to continue studying other populations of these fish that seem to have this cancer and to start answering some of the questions above. And while these sorts of parasitic cancers aren’t a problem for humans (as far as we know, hopefully), the lessons we learn from them could still help us down the road, according to Dragon.
“What I hope folks take away is that cancer goes beyond humans, and genomics is a powerful tool for researching cancer and other diseases,” she said. “With this project we have a unique opportunity to research melanoma in a new way that could greatly benefit humans.”
When the first angel emptied his bowl onto the earth, grievous sores broke out on those who had the mark of the beast on the forehead or right hand (Revelation 13:16–18). These were unbelievers who worshiped the beast. The Greek term here is helkos, which can refer to an ulcer or abscess—this is not a minor rash.
AI Overview
The sores on the kingdom of the beast refer to a specific biblical plague described in the Book of Revelation, targeting those who worship the beast.
Biblical Details of the Plague
The First Bowl: An angel pours out the first bowl of God's wrath onto the earth.
The Affliction: Foul, malignant, and painful sores (or ulcers) break out on people.
The Targets: The judgment specifically strikes individuals who have received the mark of the beast and who worship its image.
A study through the book of Revelation.
Revelation 16:1-21 (NKJV)
16:1 Then I heard a loud voice from the temple saying to the seven angels, "Go and pour out the bowls of the wrath of God on the earth." 2 So the first went and poured out his bowl upon the earth, and a foul and loathsome sore came upon the men who had the mark of the beast and those who worshiped his image. 3 Then the second angel poured out his bowl on the sea, and it became blood as of a dead man; and every living creature in the sea died. 4 Then the third angel poured out his bowl on the rivers and springs of water, and they became blood. 5 And I heard the angel of the waters saying: "You are righteous, O Lord, The One who is and who was and who is to be, Because You have judged these things. 6 For they have shed the blood of saints and prophets, And You have given them blood to drink. For it is their just due." 7 And I heard another from the altar saying, "Even so, Lord God Almighty, true and righteous are Your judgments." 8 Then the fourth angel poured out his bowl on the sun, and power was given to him to scorch men with fire. 9 And men were scorched with great heat, and they blasphemed the name of God who has power over these plagues; and they did not repent and give Him glory. 10 Then the fifth angel poured out his bowl on the throne of the beast, and his kingdom became full of darkness; and they gnawed their tongues because of the pain. 11 They blasphemed the God of heaven because of their pains and their sores, and did not repent of their deeds. 12 Then the sixth angel poured out his bowl on the great river Euphrates, and its water was dried up, so that the way of the kings from the east might be prepared. 13 And I saw three unclean spirits like frogs coming out of the mouth of the dragon, out of the mouth of the beast, and out of the mouth of the false prophet. 14 For they are spirits of demons, performing signs, which go out to the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty. 15 "Behold, I am coming as a thief. Blessed is he who watches, and keeps his garments, lest he walk naked and they see his shame." 16 And they gathered them together to the place called in Hebrew, Armageddon. 17 Then the seventh angel poured out his bowl into the air, and a loud voice came out of the temple of heaven, from the throne, saying, "It is done!" 18 And there were noises and thunderings and lightnings; and there was a great earthquake, such a mighty and great earthquake as had not occurred since men were on the earth. 19 Now the great city was divided into three parts, and the cities of the nations fell. And great Babylon was remembered before God, to give her the cup of the wine of the fierceness of His wrath. 20 Then every island fled away, and the mountains were not found. 21 And great hail from heaven fell upon men, each hailstone about the weight of a talent. Men blasphemed God because of the plague of the hail, since that plague was exceedingly great.
Sermon Transcript
Revelation 16:1 says, “Then I heard a loud voice from the temple saying to the seven angels, ‘Go and pour out the bowls…”—or “vials”—“…of the wrath of God on the earth.’”
The Antichrist is thinking that he is in control, that he has created a one-world government and everyone must bow and worship him. He’s Satan’s man-of-the hour.
Revelation 16. Verse 1 says, “Then I heard a loud voice from the temple saying to the seven angels, ‘Go and pour out the bowls of the wrath of God on the earth.’”
Chapter 16 is perhaps not only the darkest chapter in Revelation, but it is one of the darkest chapters in the entire Bible.
In chapter 16, we move from the parenthetical section of chapters 10-15 to the chronological section of chapter 16. Then chapters 17-18 will be the next parenthetical section. The narrative or chronological section picks up again in chapter 19 with the Second Coming of Jesus Christ.
In Revelation 15:1, John says, “Then I saw another sign in heaven, great and marvelous: seven angels…”—here’s our introduction to them—“…having the seven last plagues, for in them the wrath of God is complete” or “filled up” or “finished.” Revelation 16:1 says, “Then I heard a loud…”—or “great” in the King James—“…voice from the temple.” The word “great” is repeated 11 times in chapter 16. So in chapter 15 we are introduced to the seven angels who have the seven plagues, and in them is the wrath of God.
The book of Revelation started with the seven seals, in chapter 6; then it went to the seven trumpets, in chapters 8-9; then in chapter 16, it moves to the seven bowls.
The King James translations says “vials,” but it was actually a bowl or what we would more often call a “saucer.” It wasn’t a deep bowl, which when poured out would take time for it to empty. It was a shallow saucer, which when poured out would empty immediately. The priests would use a saucer-like utensil. So this chapter is a picture of God’s wrath being poured out on a Christ-rejecting world.
One of the fundamental things to know about the tribulation period is that its source is from God. God will use the devil and evil men to serve His purposes. Martin Luther, the great Protestant reformer, said, “Even the devil is God’s devil.”
The study we will look at today is in three sections. The first section is in verses 2-11, the wrath of God and the first five bowls. It starts with verse 1, “Then I heard a loud voice from the temple…”—notice that the temple is in heaven—“…saying to the seven angels….” We don’t know whose voice it is, but it is “a loud voice.” A good guess is that it is the voice of God the Father saying to the seven angels, “Go and pour out the bowls of the wrath of God on the earth.”
The phrase “the wrath of God” will be repeated three or four times in our text. When we look at the attributes of God, which are attribute to His very nature and character, we see that God is love, grace, mercy, righteous, compassionate and kind, but God is also holy. And because of God’s holiness and righteousness, He must judge sin. He can’t turn His back to sin.
Now the seven angels with seven bowls, in verse 1, will pour them out right before the Second Coming of Christ. The pouring out of all these bowls happens in rapid succession. There are no pauses; it’s just one after another. It will happen at the end of the tribulation, culminating in the battle of Armageddon and in the Second Coming of Jesus Christ.
The first bowl is in verse 2. “So the first…”—that’s the first angel—“…went and poured out his bowl upon the earth.” Each one of these bowls that is poured out has a particular target. The first target is the earth and wicked mankind. “And a foul and loathsome…”—or “grievous”—“…sore came upon the men who had the mark of the beast and those who worshiped his image.” From the word “grievous” in the Greek we get our word “malignant.”
These seven plagues that will be poured out from these seven bowls—there will be seven angels, as there were seven seals, seven trumpets and seven bowls; seven is the number of completion—in them is filled the wrath of God. We read about it in chapter 15, verse 1. So this is the culmination of God’s wrath, which happens in rapid succession and with great intensity.God’s wrath is going to be poured out by these seven angels from these seven bowls onto the earth.
Notice who He pours them out upon: “upon the men who had the mark of the beast…”—that’s the “Antichrist,” chapter 13—“…and those who worshiped his…”—or “the Antichrist’s”—“…image.” So the recipients of this sore had the mark of the beast, and they worshipped his image. The hearts of these people had become so hardened that we’ll see they are unrepentant to the point that they cannot believe, so God’s wrath is poured out on them. This grievous, vexing, loathsome, malignant sore—what a horrible thing this is!
It’s interesting that the Antichrist, who they worship and whose mark they bear, was unable to heal them, even though he performed miracles during the tribulation. You’d think because they say, “Hey, we worship you! Why don’t you help us in our hour of need!” that he would.
Many of these plagues we’ll read about by these seven angels from the seven bowls correlate with the plagues that came on Egypt before the exodus. The Egyptians had boils break out all over their bodies in the sixth plague, in Exodus 9:9. The same word taken from the Hebrew to the Greek for “boils” would be the word “sores,” in the Septuagint, the Greek translation of the Old Testament. So there are many parallels between the judgments in Exodus and the judgments of the seven bowls by the seven angels in our text.
Now we have the second bowl, in verse 3. This one is targeted on the sea. “Then the second angel poured out his bowl on the sea, and it…”—that’s “the sea”—“…became blood as of a dead man; and every living creature in the sea died.” It doesn’t say that it became blood; it became “as” blood.
Under the second trumpet judgment, one-third of the sea became blood and one-third of its sea creatures died. Now we see the entire sea turning to blood and all its sea creatures dying. It’s not specified what “sea” this is, but the word translated “sea” could refer to all the oceans of the earth.
Some try to explain these plagues in natural terms. It’s possible that God uses natural ways. Some say it’s the red tide. But the red tide doesn’t cause everything to die in the ocean and doesn’t destroy the ocean. I hardly think that’s the case.
Some say that the “sea,” in verse 3, could be the Mediterranean Sea. That’s possible, but the Scriptures seem to indicate more that it is a universal judgment on the whole world. “Every living creature in the sea died.”
Then in rapid succession we have the third angel, in verses 4-7. This time His judgment is upon the rivers and fresh-water systems of the earth. “Then the third angel poured out his bowl on the rivers and springs of water, and they became blood.” They didn’t become “as blood” but actual blood. This is a divine, supernatural judgment on earth. These plagues are so bad that there is no question in peoples’ minds of their source; they come from God Himself.
In Egypt, the Nile River turned to blood. That was one of the plagues, a judgment upon the Egyptians.
“And I heard the angel of the waters…”—apparently there is an angel that oversees the waters—“…saying: ‘You are righteous, O Lord, the One who is and who was and who is to be…”—that’s the eternal nature of God—“…because You have judged these things. For they have shed the blood of saints and prophets.’” “‘And You have given them blood to drink. For it is their just due.’” So in heaven they say, “God, you’re right on; your judgments are righteous. They’ve killed the saints and the prophets, and now You’ve given them blood to drink.”
It’s interesting that Pharaoh in Egypt was having the male babies thrown into the Nile River to kill them. But God had Pharaoh’s army go into the Red Sea, and they drowned there. “Whatever a man sows, that he will also reap.”
Then we have the fourth bowl, in verses 8-9. This time the fourth angel poured out his bowl on the sun; it’s a solar judgment. “Then the fourth angel poured out his bowl on the sun, and power was given to him to scorch men with fire.” In an earlier judgment, “the sun became darkened as black sackcloth of hair.” And now the sun has intensified in its heat. “And men were scorched with great heat, and they blasphemed the name of God who has power over these plagues; and they did not repent and give Him glory.”
So God has the control and power over these plagues. God is sovereign. No one can thwart His purposes. He gives these plagues to sinful men, but they do not repent, and they do not give Him glory. How sad is that.
Again, a lot of people like to hold a natural explanation for this bowl being poured out on the sun. We have “global warming,” which is quite popular today. They find it here in the Scriptures. But this is a supernatural intervention of God during the tribulation. It’s not anything like the earth so called “warming up” today. This is God punishing mankind on the earth.
Malaki 4:1 says, “‘For behold, the day is coming, burning like an oven, and all the proud, yes, all who do wickedly will be stubble. And the day which is coming shall burn them up,’ says the Lord of hosts.” I believe that is a prophecy of this event in the day of the Lord, when God allows the sun to actually scorch men with intense heat, and people curse God at this time.
Now we move to the fifth bowl, in verses 10-11. This time it’s poured out on the seat, the throne or the kingdom of the Antichrist. “Then the fifth angel poured out his bowl on the throne of the beast…”—which is “the Antichrist”—“…and his kingdom became full of darkness.” The ninth plague in Egypt, in Exodus 10, was darkness, but there was light in the land of Goshen, where the people of Israel were. This was oppressive darkness. “And they gnawed their tongues because of the pain. They blasphemed the God of heaven because of their pains and their sores.” This happened in verse 2 during the first bowl plague. And by the time you get to this fifth bowl, they are still having these malignant sores. “And [they] did not repent of their deeds.”
This is the second time in this passage that they did not repent. The Greek word is “metanoia.” It means they did not change their minds. I believe it’s because their minds become reprobate, Romans 1. The word “reprobate” means “doesn’t work”; it’s broken. They don’t think correctly. So they curse God and don’t repent. And they gnaw their tongues in pain in this darkness. They also blaspheme God.
The Bible indicates that you can reach a point of no return, where your heart spiritually atrophies. You were made for God. You were made to know God. You were made to be in fellowship with God. If you reject the Light, refuse to repent and harden your heart, then your heart will atrophy. You’ll reach the point where the Bible says, “Therefore they could not believe.” These people who this judgment is coming upon are the people who have crossed that line. They’ve been deceived. They cannot be saved. There comes a time when God’s patience will run out. The wrath of God in the bowls is the last series of plagues poured out on mankind.
Now remember when Jesus died on the Cross? This darkness is interesting. He was on the Cross from 9:00 a.m. until 3:00 p.m., six hours. But from high noon until 3:00 p.m., there was darkness. When the darkness came, Jesus cried, “Eli, eli, lama sabachthani,” or “My God, My God, why have You forsaken Me?” Think about that. Then God covered the earth with a veil of darkness.
In the garden of Gethsemane, Jesus said, “O My Father, if it is possible, let this cup pass from Me; nevertheless, not as I will, but as You will.” Then He drank the cup of God’s wrath. When Jesus died on the Cross, not only did our sins get placed upon the sinless Son of God, but God’s wrath was poured out upon Jesus. We can’t even fathom that. Jesus was forsaken by His Father so that we would never have to be forsaken by God.
But these people in our text did not trust and believe in Christ. They rebelled against Him and worshipped the image of the Antichrist and took his mark. So there is darkness over the whole earth.
Now the sixth bowl is in the second section, the war of Armageddon, in verses 12-16. Verses 1-11 is the wrath of God, and verses 12-16 is the war of Armageddon in this sixth bowl. We’re almost complete in this time of God’s wrath. “Then the sixth angel poured out his bowl on the great river Euphrates, and its water was dried up, so that the way of the kings from the east might be prepared. And I saw three unclean spirits…”—these are demons—“…like frogs coming out of the mouth of the dragon, out of the mouth of the beast…”—or “the Antichrist”—“…and out of the mouth of the false prophet.”
This false prophet was the beast that came out of the land, in chapter 13. “For they are spirits of demons, performing signs, which go out to the kings of the earth and of the whole world, to gather them to the battle of that great day of God Almighty. ‘Behold, I am coming as a thief.’” This is the Lord speaking. “‘Blessed is he who watches, and keeps his garments, lest he walk naked and they see his shame.’ And they gathered them together to the place called in Hebrew, Armageddon.” Armageddon means “hill of Megiddo.” It’s on the plains of Esdraelon.
Notice that this sixth bowl is expanded; there’s more information about it than the others. First, it is poured out “on the great river Euphrates.” It’s interesting that the Tigris and the Euphrates rivers come together between Iraq and Iran, and they flow into the Persian Gulf. They originate in Turkey at the base of Mount Ararat, where Noah’s ark rested. The Euphrates River flows about 1,800 miles in length. It’s about 1,200 yards in width and 30 feet deep. It’s interesting that God dries it up, so the kings of the east are able to cross it to get into the Middle East.
Israel is a natural land bridge between the continents of Europe, Asia and Africa. This area is the birthplace of humanity, where the Garden of Eden was located; mankind started here.
The battle of Armageddon will be in the Valley of Jezreel. The mountain there is called Megiddo. From it we get our word Armageddon or “hill of Megiddo.” It’s a valley in the middle of Israel where all the armies of the world will gather together at the end of the tribulation just before and during the Second Coming of Jesus Christ. This battle will be raging, and mankind will have the ability to kill himself off planet earth when Jesus Christ comes in His Second Coming. So we still have World War III ahead of us, but the church will have already been “caught up” to be with Christ and will come back with Him in His Second Coming.
The Valley of Jezreel or the plains of Esdraelon is in the central valley of Israel. It is inland a little ways from Haifa and from the Dead Sea. It runs for miles and miles and is surrounded by mountains. Napoleon overlooked this valley and said, “What a great place to bring all the armies of the world together in a battle.” It was here that Barak fought his battle. It was here that Gideon fought his battle. It’s where King Saul was killed on Mount Gilboa. So there were many battles here in the past, and there will be a battle here in the future.
So in verse 13, demons come out of the mouth of the dragon, the beast and the false prophet. Bible students have called this “the unholy trinity.” Just as there is God the Father, God the Son and God the Holy Spirit—one God in three Persons—so Satan has his imitation trinity. The dragon is Satan, the beast is the Antichrist and there is the false prophet, which is the counterpart to the Holy Spirit. The Bible doesn’t call it “the unholy trinity,” but it is an interesting parallel to see in the Scriptures.
In Joel 3:14, he said, “Multitudes, multitudes in the valley of decision!” In Revelation 19, when the Lord comes back, He destroys the Antichrist and the false prophet, puts an end to war and He sets up His kingdom on earth for 1,000 years. So this is the Lord coming back to end man’s war on earth.
And what happened in Egypt? Frogs everywhere. Pharaoh freaked out and told Moses, “Get rid of the frogs!”
Moses asked Pharaoh, “When would you like me to get rid of the frogs?”
Pharaoh said, “Tomorrow.”
So God brings these demons or “unclean spirits,” but they look like frogs.
So this is just a word to those on the earth during the tribulation who still need to repent that He is “coming as a thief” and be ready and watching.
Verse 16, “And they gathered them together to the place called in Hebrew, Armageddon.”
In the last section, in verses 17-21, we have the wasting of the earth. Environmentalists are all worried about what we’re doing to planet earth.
“Then the seventh angel poured out his bowl into the air.” Now remember that Satan is called “the prince of the power of the air.” So this is no doubt directed toward Satan’s kingdom. “And a loud voice came out of the temple of heaven, from the throne, saying, ‘It is done!’”
“It is complete” or “It is done.” Either you rest in the finished work of Jesus Christ on the Cross or you drink the cup of God’s wrath upon the earth.
Verse 18, “And there were noises and thunderings and lightnings; and there was a great earthquake, such a mighty and great earthquake as had not occurred since men were on the earth. Now the great city…” It doesn’t tell us what great city, but it might be Babylon or probably Jerusalem. When Christ comes back He comes to Mount Olivet, and it’s split down the middle with all these topographical changes in the earth. It “…was divided into three parts, and the cities of the nations fell.” All the big cities of the nations fell.
Verse 19, “And great Babylon was remembered before God, to give her the cup of the wine of the fierceness of His wrath.” We’ll get that in chapters 17 and 18. “Then every island fled away, and the mountains were not found.”
But He’s not done yet. “And great hail from heaven fell upon men, each hailstone about the weight of a talent.” A talent is 100 pounds. Can you imagine hailstones coming out of heaven from God weighing 100 pounds each?! “Men blasphemed God because of the plague of the hail, since that plague was exceedingly great.”
So God pours out His wrath on this Christ-rejecting world. And all the world is shaken until “the things which cannot be shaken may remain.”
Also:
Revelation 16:2
Also:
Seven Bowls Of God’s Wrath
