Which mechanism best explains why cigarette smoking acts as a cofactor specifically for squamous cell carcinoma of the cervix?

• A Systemic immunosuppression through CD4 T-cell depletion
• B Concentration of tobacco carcinogens and nicotine metabolites in cervical mucus acting on the transformation zone ✓
• C Direct induction of HPV E6 and E7 expression from the viral genome
• D Conversion of retinol to carcinogenic metabolites within basal keratinocytes

Explanation

Smoking is a well-established cofactor for squamous cervical cancer. Tobacco-specific nitrosamines such as NNK and nicotine metabolite cotinine are measurable in cervical mucus at concentrations higher than in serum, exerting local genotoxic effects on metaplastic cells of the transformation zone. CD4 depletion characterises HIV-related immunosuppression, not smoking. Smoking does not transactivate viral oncogenes directly, and it is notably weak as a cofactor for glandular lesions.

Reference: Robbins and Cotran Pathologic Basis of Disease, 10th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.