Cadmium and Chromium exposure associated with DNA hypermethylation of p16 tumor suppressor gene: a case–control study from endemic region of northern India

This study investigates the environmental impact of urbanization on water quality in Greater Noida, a rapidly developing region in India. Thirty groundwater samples were collected from five villages during the pre-monsoon season using sterilized polypropylene bottles, and samples were acidified and digested with concentrated nitric acid prior to analysis. Chromium (Cr) and cadmium (Cd) concentrations in water were determined using Atomic Absorption Spectrophotometry (AAS), with mean pre-monsoon concentrations of 0.436 ± 0.237 ppb for Cr and 0.224 ± 0.091 ppb for Cd. A case-control study involving 25 cancer patients and 25 healthy individuals was conducted to explore the potential health effects of heavy metal exposure through drinking water. Blood samples were analyzed for Cd and Cr levels, and p16 gene promoter hypermethylation was assessed in whole blood leukocytes using methylation-specific PCR (MSP). The frequency of p16 hypermethylation was significantly higher in the exposed group (64%) compared to controls (8%) (p = 0.002). These findings demonstrate a strong association between heavy metal exposure and p16 hypermethylation, emphasizing the need for comprehensive monitoring, control measures, and remediation strategies to address environmental contamination and safeguard public health in swiftly urbanizing regions like Greater Noida.