12/07/2026
Oncogenesis and Molecular Mechanics: How Viruses Corrupt DNA and Trigger Cancer (The Story Behind KRAS, HRAS, and Myc)
Infectious Causes of Cancer
Whether you are personally interested in oncology, know someone battling this disease, or simply want to expand your scientific knowledge—this biological mechanism is worth understanding.
Genes such as KRAS (Kirsten Rat Sarcoma), HRAS (Harvey Rat Sarcoma), and NRAS are deeply involved in a wide spectrum of human malignancies, including leukemias, sarcomas, neuroblastomas, malignant melanoma, bronchopulmonary carcinoma, thyroid cancer, and colorectal cancer.
In their normal state, these genes act as cellular switches, regulating division through precise ON/OFF signaling. However, when they become corrupted by mutations, the switch gets permanently stuck in the ON position, leading to continuous, uncontrolled cell multiplication.
The abbreviation RAS actually originates from Rat Sarcoma Virus. Back in 1911, researcher Peyton Rous demonstrated that leukemia and sarcoma in chickens could be transmitted via cell-free tumor filtrates obtained by grinding up diseased tissues. This groundbreaking work officially identified the viral etiology of certain neoplastic diseases.
Between 1960 and 1965, oncology researchers Kirsten and Harvey conducted laboratory tests on rodents. Their initials were later appended to the RAS acronym to honor their findings. They observed that specific types of viruses, under well-defined conditions, could directly initiate tumorigenesis upon infecting a host. The foundation of this model was the rat sarcoma virus (RAS).
To achieve this, the pathogen must be a specific type of virus known as a RETROVIRUS. Retroviruses store their genetic blueprint in RNA instead of DNA and carry two crucial enzymes:
Reverse Transcriptase: This enzyme operates within the cell nucleus, reverse-writing the corrupted viral RNA code back into human or animal DNA.
Integrase: This enzyme acts like molecular scissors. It cuts the ends of the host's DNA strands and splices in the new, corrupted viral DNA sequence. From that moment on, the cell is reprogrammed to multiply chaotically and follow an entirely new, hijacked set of instructions.
Through this mechanism, scientists were able to create controlled disease models in laboratory rat cohorts—for instance, inoculating one group with a specific virus to induce leukemias, while another group received a strain that triggered sarcomas.
The Myc Gene
The name Myc comes from Myelocytomatosis, a form of avian leukemia. The initial viral links were discovered in 1964 while researchers were studying an aggressive avian retrovirus that rapidly triggered tumors.
When the human Myc gene undergoes mutations and becomes an active oncogene, it drives highly aggressive forms of cancer. In fact, it is implicated in 50% to 70% of all human malignancies, including leukemias, lymphomas, high-grade ovarian cancer, triple-negative breast cancer, squamous cell lung carcinomas, colorectal cancer, and prostate cancer.
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