Background: Altered or decreased immune function in the aging population, in persons with HIV, and in transplant patients may increase the risk of cancer in these groups. Immune surveillance indicates that deficiencies in recognizing and removing cells with pre-malignant changes allow these cells to proliferate and progress to a malignant tumor. However, biologic and epidemiologic evidence supporting the theory of immune surveillance, particularly in humans, is incomplete. Hypothesis: Decreased immunocompetency contributes to the development of non-melanoma skin cancers, basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), in the aging population. Methods: This pilot study uses a case-control study design to investigate the immune status of aging persons with and without a history of BCC and/or SCC. Candidates for the study are those with skin lesions suspected to be nonmelanoma skin cancer (BCC or SCC), requiring biopsy. Other inclusion criteria are men and women between the ages of 40 and 85 years. Importantly, the proposed study participants are drawn from the counties of the Texas Lower Rio Grande Valley where between 84% and 97% of the population are of Hispanic decent. The physician excludes persons with previous nonmelanoma or melanoma skin cancer diagnoses, previous cancer diagnosis, autoimmune diseases, immunosuppressive diseases, and those persons undergoing immunosuppressive drug therapy (i.e., transplant recipients). In addition, patients with other skin conditions (i.e., psoriasis) are excluded. Cases are those participants diagnosed with BCC or SCC as determined by biopsy results. The current immune parameters examined include the Complete Blood Count (CBC) with Differential, CD4+ helper to CD8+ cytotoxic T-cell ratio, and naïve to memory T-cell ratio. Data assessing sun and other exposure history, and family health history is collected by questionnaire. Results: The study is in progress, and preliminary data will be presented on the first 15 participants who have completed the study. Conclusions: These data will provide important baseline information about the role of waning immunity in elderly skin cancer patients that may contribute to susceptibility and progression of cancer. The long-term goal of this research program is to identify markers of immune function that are altered in persons with cancer for use as early biomarkers of cancer risk, and as possible prevention and/or treatment targets.
[Proc Amer Assoc Cancer Res, Volume 47, 2006]