A new twist in cancer's DNA modification
New findings indicate that some anti-cancer drugs may paradoxically cause cancer
Scientists have known for several years that hypermethylation, a chemical modification of DNA in which multiple small carbon groups help to deactivate the genetic material, is a major mechanism in many cancers.
A wide range of chemotherapy agents act by promoting demethylation - removing those carbon groups - in hope of restoring the tumor cell's DNA to its normal state. But there is a major unexpected complication: New research from Hopkins suggests that demethylation can actually cause certain cancers as well.
"As it turns out, for almost the past half-decade, people have been focused on hyper-methylation tumor suppressor genes, and nobody's figured out how to look at the footside in a genome fashion - the footside being the activation of oncogenes," Joseph Califano, a head and neck surgeon and one of the lead investigators of this study, said.
In past studies of different cancers, various examples of hypomethylation causing the overactivation of proto-oncogenes, or cancer-causing genes, have been reported. These observations have concerned cancers such as gastric cancer, leukemia, colon cancer and small cell lung cancer.
Oncogenes and proto-oncogenes are those that drive increased activity of the cell cycle. When these genes are active, the cell is more likely to divide - and out-of-control cell division is the ultimate cause of cancer. Regulation of oncogenes and proto-oncogenes by the cell is therefore very important.
"Demethylating agents are now in clinical trials so we don't have definitive data. You just don't know what the rate of secondary cancer growth would be if you activated this pathway," Califano said.
The researchers, including members of the Department of Otolaryngology - Head and Neck Surgery, the Department of Surgery, Division of Plastic and Reconstructive Surgery, Division of Oncology Biostatistics and the Department of Oncology at the Hopkins Medical Institutions, have identified a connection between these seemingly unrelated examples in a protein called BORIS, which coordinates the activation of proto-oncogenes in cancerous tissue.
A wide range of chemotherapy agents act by promoting demethylation - removing those carbon groups - in hope of restoring the tumor cell's DNA to its normal state. But there is a major unexpected complication: New research from Hopkins suggests that demethylation can actually cause certain cancers as well.
"As it turns out, for almost the past half-decade, people have been focused on hyper-methylation tumor suppressor genes, and nobody's figured out how to look at the footside in a genome fashion - the footside being the activation of oncogenes," Joseph Califano, a head and neck surgeon and one of the lead investigators of this study, said.
In past studies of different cancers, various examples of hypomethylation causing the overactivation of proto-oncogenes, or cancer-causing genes, have been reported. These observations have concerned cancers such as gastric cancer, leukemia, colon cancer and small cell lung cancer.
Oncogenes and proto-oncogenes are those that drive increased activity of the cell cycle. When these genes are active, the cell is more likely to divide - and out-of-control cell division is the ultimate cause of cancer. Regulation of oncogenes and proto-oncogenes by the cell is therefore very important.
"Demethylating agents are now in clinical trials so we don't have definitive data. You just don't know what the rate of secondary cancer growth would be if you activated this pathway," Califano said.
The researchers, including members of the Department of Otolaryngology - Head and Neck Surgery, the Department of Surgery, Division of Plastic and Reconstructive Surgery, Division of Oncology Biostatistics and the Department of Oncology at the Hopkins Medical Institutions, have identified a connection between these seemingly unrelated examples in a protein called BORIS, which coordinates the activation of proto-oncogenes in cancerous tissue.
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Cancer Cure
posted 4/15/09 @ 5:38 AM EST
In man's effort to help people, a lot of times it makes things worse. Vioxx was to help with pain and it worked. It kiled people which ended their pain. (Continued…)
Cardiovascular Health
posted 10/24/09 @ 12:36 AM EST
This reminds me of the saying "With friends like these, who needs enemies." Imagine paying good money to get cancer. That adds insult to injury.
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