Which subtype of human papilloma virus has maximum chances of causing carcinoma cervix: September 2012, March 2013
**Core Concept**
Human papillomavirus (HPV) is a significant risk factor for cervical cancer, with certain subtypes being more carcinogenic than others. The carcinogenic potential of HPV is closely linked to the presence of specific viral oncogenes, such as E6 and E7, which disrupt normal cell cycle regulation.
**Why the Correct Answer is Right**
HPV-16 is the most common high-risk subtype associated with cervical cancer, responsible for approximately 55-60% of all cervical cancer cases. This subtype contains a potent E6 protein that binds to and inactivates the tumor suppressor protein p53, leading to uncontrolled cell proliferation and malignant transformation. The E7 protein of HPV-16 also inactivates the retinoblastoma protein (pRb), further contributing to oncogenesis.
**Why Each Wrong Option is Incorrect**
**Option A:** HPV-6 is primarily associated with genital warts, which are a benign condition. While HPV-6 can cause some cancers, it is not as strongly linked to cervical cancer as HPV-16.
**Option B:** HPV-18 is another high-risk subtype, responsible for approximately 10-15% of cervical cancer cases. However, its carcinogenic potential is lower than that of HPV-16.
**Option C:** HPV-11 is a low-risk subtype commonly associated with genital warts, similar to HPV-6.
**Clinical Pearl / High-Yield Fact**
HPV vaccination is highly effective in preventing cervical cancer, with the quadrivalent vaccine (Gardasil) protecting against HPV-6, 11, 16, and 18. This underscores the importance of vaccination in preventing cervical cancer, particularly in young women before they become sexually active.
**Correct Answer: D. HPV-16.**