Early-onset of sporadic basal-cell carcinoma: germline mutations in the TP53, PTCH, and XPD genes

BACKGROUND: Basal cell carcinoma (BCC) is the most common non-melanoma skin cancer in the Western world. The objective of this study was to examine together germline mutations in the TP53, PTCH, and XPD genes as risk factors for developing BCC at a young age. We hypothesized that mutations in these genes significantly increase the risk of early-onset BCC (< or = 35 years). METHODS: The PCR, DNA sequencing and Restriction Fragment Length Polymorphisms methods were utilized to study eight Puerto Rican patients with a confirmed diagnosis of BCC before age 35. RESULTS: A novel germline mutation (T:A transversion) was identified at the exon 4, codon 50 of the TP53 gene of one BCC patient. No other mutations were found at the TP53 or PTCH genes. The presence of the XPD mutant allele is associated with a seven-fold increase in risk (OR = 7.0, p = 0.03) for developing BCC prior to age 35. In addition, the DNA Repair Capacity (DRC) of these BCC patients showed a 47% reduction that was significant in relation to age-matched controls (p = 0.021). However, the XPD mutant allele was not associated with the decrease in DRC observed in BCC participants. CONCLUSIONS: The evaluated population presented BCC before age 35, a phenomenon that is so rare as to make very difficult the study of this subpopulation with a larger sample size. The results of this study, suggest that the XPD Lys751Gln polymorphism may have a significant role in the development of early-onset BCC in the Puerto Rican population.

Risk factors for atopic dermatitis in southern Puerto Rico

BACKGROUND: Little is known about the risk factors and exposures to aeroallergens in subjects with atopic dermatitis (AD) in Southern Puerto Rico. The objective was to determine the prevalence of skin reactions to aeroallergens and to analyze self-reported risk factors in AD patients and a nonallergic control population. METHODS: A cross-sectional study was conducted which included 726 AD patients and 313 nonallergic control subjects. Skin tests were conducted and a questionnaire was self-applied to all participants. RESULTS: Seventy six percent of the AD patients showed at least one positive skin reactions to aeroallergens. Of these, half had positive skin reactions to dust mites, and one third to Periplaneta americana. A low prevalence of positive skin reactions to dog, cat, plant and fungal allergens was detected. Co-sensitivitity between mites and cockroaches was 30%. The maximum skin reactivity to mites was at 10-19 years of age declining thereafter while skin reactivity to dogs, and plants increased with age. No significant differences in the prevalence of skin reactions was observed between the male and female AD population. CONCLUSIONS. Of the aeroallergens tested, those derived from dust mites are the most frequent sensitizing agents in the AD patients. Data also showed that the mites B. tropicalis and E. maynei are also important sources of sensitization. Our study show that young patients specially those between the age of 10-19 age group are the most allergic. Being female, or having an asthmatic father are significant risk factors associated with allergen sensitivity in the AD population.