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.

Hepatitis C patients in Puerto Rico have an altered iron balance.

Iron overload is a major concern in hepatitis C virus (HCV) infection because excess iron can promote hepatocyte damage by activating iron-mediated lipid peroxidation. This may also facilitate viral replication. The objective of this pilot study was to test the hypothesis that Puerto Rican HCV patients have an altered serum iron (SIR) profile. Twenty-three HCV patients and 38 non-HCV controls were compared in terms of their serum iron, iron-binding capacity, percent saturation of transferrin, available binding capacity, and ferritin. Statistically significant differences (p < 0.01, Student's t-test) were found between the HCV patients and the non-HCV controls for SIR, transferrin saturation, and ferritin. The mean SIR concentration and transferrin saturation were 25% higher in HCV patients relative to controls. HCV patients had a mean ferritin value 48% higher than controls. These pilot study data indicate that Puerto Rican HCV patients have an altered iron balance and may be more susceptible to iron-induced oxidative stress.

Epidemiological trends of melanoma in Puerto Rico from 1975-1991.

The purpose of this study was to determine the crude and age-adjusted incidence rates of melanoma for residents of Puerto Rico from 1975 to 1991. This is part of an ongoing NASA study aimed at estimating whether melanoma and cataracts have increased in Puerto Rico since 1978 because of potential stratospheric ozone depletion and increased ultraviolet-B (UV-B) radiation. Calculating the percent change from their lowest values in 1978 to 1991, the age-adjusted incidence rate of melanoma increased 528% for males and 200% for females in 13 years.

Epidemiological trends of melanoma in Puerto Rico from 1975-1991

The purpose of this study was to determine the crude and age-adjusted incidence rates of melanoma for residents of Puerto Rico from 1975 to 1991. This is part of an ongoing NASA study aimed at estimating whether melanoma and cataracts have increased in Puerto Rico since 1978 because of potential stratospheric ozone depletion and increased ultraviolet-B (UV-B) radiation. Calculating the percent change from their lowest values in 1978 to 1991, the age-adjusted incidence rate of melanoma increased 528% for males and 200% for females in 13 years

Photosynthetic response to elevated temperature in the symbiotic dinoflagellate Symbiodinium microadriaticum in culture.

Elevated temperature (28-34 degrees C) has been hypothesized as the primary cause of the loss of algal endosymbionts in coral reef-associated invertebrates, a phenomenon observed on a world-wide scale over the last decade. In past studies of this "bleaching" phenomenon, there has been an underlying assumption that temperature adversely affects the animal hosts, the algae thereby being relegated to a more passive role. Because photosynthesis is a sensitive indicator of thermal stress in plants and has a central role in the nutrition of symbiotic invertebrates, we have tested the hypothesis that elevated temperature adversely affects photosynthesis in the symbiotic dinoflagellate Symbiodinium microadriaticum. The results, based on analyses of light-mediated O2 evolution and in vivo fluorescence, indicate that photosynthesis is impaired at temperatures above 30 degrees C and ceases completely at 34-36 degrees C. These observations are discussed in the context of possible mechanisms that may function in the disassociation of algal-invertebrate symbioses in response to elevated temperature.