Study of the frequencies of CYP1A1 gene polymorphisms and glutathione S-transferase mu1 gene in primary breast cancers: an update with an additional 114 cases.

We studied the polymorphisms m1 (Msp1 restriction site) and m2 (codon Val substitution) of CYP1A1 gene and the copy number of glutathione S-transferase mu1 (GSTM1) gene on 487 DNA of breast cancer primary tumours from Caucasian group. Tumours of patients aged 55 years and under at diagnosis presented a great proportion of wild m1 (-/-) genotype; 83.6% vs. 69.5% (p < 0.0006), and a higher percentage of copy number of GSTM1 equal or under one copy; 65.2% vs. 53.4% (p < 0.011) for older patients m1 and m2 variants are closely linked (p < 0.0000). Tumour with a low copy number of GSTM1 is correlated with high histological grading (p < 0.01) and high Cathepsin D concentrations (p < 0.02). The combinations of different genotypes showed that association wild m1 (-/-) genotype and copy number of GSTM1 inferior or equal to one copy is correlated with an early onset of breast cancer primary tumour 44% vs. 6.4% for m1 (-/+) or (+/+) genotype and copy number of GSTM1 superior to one (p < 0.0000). The CYP1A1 gene wild form seems to be associated with early cancer development in Caucasian patients.