Objective: To examine risk factors for the development of cutaneous squamous cell carcinoma (SCC) in a group of human immunodeficiency virus (HIV)-infected patients, including evaluation and detection of epidemiologic risk factors of human papillomavirus (HPV) and p53 expression.
Design: Case-control study during a 3-year period.
Setting: Dermatologic referral center.
Patients: Thirty-three HIV-infected patients who had 97 SCCs were compared with 24 HIV-infected patients who had 70 basal cell carcinomas (BCCs).
Main outcome measures: Age, skin type, amount of sun exposure, actinic damage, family history of skin cancer and history of smoking and warts. Specimens of SCC and BCC were examined for HPV using polymerase chain reaction. Presence of p53 was examined using immunohistochemical analysis. Specimens from tumor-free, non-sun-exposed areas from these same patients were used as controls.
Results: Risk factors for the development of both types of carcinoma included fair skin type and excessive sun exposure (> 6 h/d during the previous 10 years). The HIV-infected patients with SCCs tended to have outdoor occupations. The location of SCCs favored the head and neck; BCCs were located on the trunk. Patients with SCCs had later-stage HIV disease than did patients with BCCs. Half of the patients with SCC had a history of genital or nongenital warts. Seventy-one percent (17/24) had a smoking history. No statistical difference existed between patients with SCCs and BCCs for history of smoking or warts. Human papillomavirus was not found in most of our SCC, BCC, or control specimens. However, 92% (22/24) of the SCC specimens and 90% (18/20) of the BCC specimens stained for p53. Control specimens from non-sun-exposed skin of HIV-infected patients did not stain for p53. Epidermal staining was present in 95% (17/20) of tissue adjacent to SCCs and 47% (7/15) of tissue adjacent to BCCs. A significantly positive correlation existed between the amount of sun exposure and the amount of p53 staining seen in adjacent epidermal tissue (r = 0.07; P = .01).
Conclusions: Risk factors for the development of SCCs and BCCs in HIV-infected patients are similar: fair skin type and excessive sun exposure. Our study does not support that HPV is an oncogenic factor in the development of these cutaneous tumors but provides evidence that p53 overexpression may play a role.