Polymorphisms and haplotypes in the cytochrome P450 17A1, prolactin, and catechol-O-methyltransferase genes and non-Hodgkin lymphoma risk

Expression of prolactin and of prolactin and estrogen receptors in lymphocytes, bone marrow, and lymphoma cell lines suggests that hormonal modulation may influence lymphoma risk. Prolactin and estrogen promote the proliferation and survival of B cells, factors that may increase non-Hodgkin lymphoma risk, and effects of estrogen may be modified by catechol-O-methyltransferase (COMT), an enzyme that alters estrogenic activity. Cytochrome P450 17A1 (CYP17A1), a key enzyme in estrogen biosynthesis, has been associated with increased cancer risk and may affect lymphoma susceptibility. We studied the polymorphisms prolactin (PRL) -11496>T, CYP17A1 -34T>C, and COMT 108/158Val>Met, and predicted haplotypes among a subset of participants (n = 308 cases, n = 684 controls) in a San Francisco Bay Area population-based non-Hodgkin lymphoma study (n = 1,593 cases, n = 2,515 controls) conducted from 1988 to 1995. Oral contraceptive and other hormone use also was analyzed. Odds ratios (OR) for non-Hodgkin lymphoma and follicular lymphoma were reduced for carriers of the PRL -1149TT genotype [OR, 0.64; 95% confidence interval (95% CI), 0.41-1.0; OR, 0.53; 95% CI, 0.26-1.0, respectively]. Diffuse large-cell lymphoma risk was increased for those with CYP17A1 polymorphisms including CYP17A1 -34CC (OR, 2.0; 95% CI, 1.1-3.5). ORs for all non-Hodgkin lymphoma and follicular lymphoma among women were decreased for COMT IVS1 701A>G [rs737865; variant allele: OR, 0.53; 95% CI, 0.34-0.82; OR, 0.42; 95% CI, 0.23-0.78, respectively]. Compared with never users of oral contraceptives, a 35% reduced risk was observed among oral contraceptive users in the total population. Reduced ORs for all non-Hodgkin lymphoma were observed with use of exogenous estrogens among genotyped women although 95% CIs included unity. These results suggest that PRL, CYP17A1, and COMT may be relevant genetic loci for non-Hodgkin lymphoma and indicate a possible role for prolactin and estrogen in lymphoma pathogenesis.