Abnormalities of Rb-pathway components are common in the formation of cancer. The immunostaining for cyclin D1 and p16 protein was applied on 1 mm serial tissue microarray (TMA) paraffin sections. Tissue microarray (TMAs) is potentially a good method to find the molecular features of the genes and expressions of them. The aim of this study was to evaluate the protein expressions of cyclin D1 and p16 genes in squamous cell carcinomas (SCCs) of skin and compare with the normal skin tissue. Twenty-five cases of cutaneous SCCs expressed cyclin D1 and p16 proteins. All SCCs samples on the slides showed positive protein expressions of cyclin D1 and p16 genes. Our findings suggested that the increased protein expressions of cyclin D1 and p16 genes might lead to aberrant expressions of these proteins in the affected tumor cells. This study demonstrated that cell cycle controlled deregulation and uncontrolled cell cycle progression might result in the carcinogenesis.
We evaluated the possible influence of glutathione S-transferase mu (GSTM1) and glutathione S-transferase theta (GSTT1) genes on genetic damage due to occupational exposure, which contributes to accelerate ageing. This study was conducted on 120 car auto repair workshop workers exposed to occupational hazards and 120 controls without this kind of exposure. The null and non-null genotypes of GSTM1 and GSTT1 genes were determined by multiplex PCR. Micronucleus frequency, Comet tail length and relative telomere length differences between the null and non-null genotypes of the GSTM1 gene were significantly greater in the exposed group. Lack of GSTT1 did not affect the damage biomarkers significantly (P > 0.05), while lack of GSTM1 was associated with greater susceptibility to genomic damage due to occupational exposure. It was concluded that early ageing is under the influence of these genes and the environmental and socio-demographic factors. Duration of working time was significantly associated with micronucleus frequency, Comet tail length and relative telomere length.