Genetic variants associated with arsenic susceptibility: study of purine nucleoside phosphorylase, arsenic (+3) methyltransferase, and glutathione S-transferase omega genes.

Background: Individual variability in arsenic metabolism may underlie individual susceptibility toward arsenic-induced skin lesions and skin cancer. Metabolism of arsenic proceeds through sequential reduction and oxidative methylation being mediated by the following genes: purine nucleoside phosphorylase (PNP), arsenic (+3) methyltransferase (As3MT), glutathione S-transferase omega 1 (GSTO1), and omega 2 (GSTO2). PNP functions as arsenate reductase; As3MT methylates inorganic arsenic and its metabolites; and both GSTO1 and GSTO2 reduce the metabolites.

Arsenic-induced health effects and genetic damage in keratotic individuals: involvement of p53 arginine variant and chromosomal aberrations in arsenic susceptibility.

In West Bengal, India, more than 6 million people are exposed to arsenic through drinking water. Chronic arsenic exposure results in several multisystemic non-cancerous as well as cancerous effects in humans. Among non-cancerous effects, arsenic-specific skin lesions, conjunctivitis, peripheral neuropathy and respiratory diseases are prominent.

Increased chromosome aberration frequencies in the Bowen's patients compared to non-cancerous skin lesions individuals exposed to arsenic.

Cytogenetic biomarkers are essential for assessing environmental exposure that can predict adverse human health effects such as cellular damage. Chromosomal aberrations are the most important cytogenetic end-points successfully used for the cancer risk assessment of populations occupationally or environmentally exposed to different toxic chemicals. Previous reports suggest that, increased frequency of chromosomal aberration (CA), in peripheral blood lymphocytes, is a predictor of cancer.

Association of specific p53 polymorphisms with keratosis in individuals exposed to arsenic through drinking water in West Bengal, India.

Although, more than six million people are endemically exposed to inorganic arsenic in West Bengal, India by drinking heavily contaminated groundwater, only about 300,000 people show arsenic induced skin lesions. This suggests that genetic variability plays an important role in arsenic induced skin lesions and skin cancers. Arsenic induced keratosis is considered as a possible precancerous state of in situ carcinoma.

Comparison of health effects between individuals with and without skin lesions in the population exposed to arsenic through drinking water in West Bengal, India.

A study was conducted to explore the effect of arsenic causing conjunctivitis, neuropathy and respiratory illness in individuals, with or without skin lesions, as a result of exposure through drinking water, contaminated with arsenic to similar extent. Exposed study population belongs to the districts of North 24 Parganas and Nadia, West Bengal, India. A total of 725 exposed (373 with skin lesions and 352 without skin lesions) and 389 unexposed individuals were recruited as study participants.