A case-control study of galactose consumption and metabolism in relation to ovarian cancer

Consumption or metabolism of dairy sugar and ovarian cancer have been linke d based on evidence that galactose may be toxic to ovarian germ cells and t hat ovarian cancer is induced in animals by depletion of oocytes. We assess ed consumption of dairy products and obtained blood for biochemical and mol ecular genetic assessment of galactose metabolism in 563 women with newly d iagnosed epithelial ovarian cancer and 523 control women selected either by random digit dialing or through lists of residents in eastern Massachusett s and New Hampshire, We observed no significant differences between cases a nd controls in usual consumption of various types of dairy products or tota l daily lactose (the principal source of galactose in the diet); nor did we find that RBC activity of either galactose-l-phosphate uridyl transferase (GALT) or galactokinase differed. The mean land SE) activity of uridine dip hospho-galactose 4'-epimerase tin micromoles per hour per gram of hemoglobi n) was, however, significantly lower (P < 0.005) in cases compared with con trols, 20.32 (0.31) versus 21.64 (0.36). Ovarian cancer cases were also mor e likely to carry the N314D polymorphism of the GALT gene, generally predis posing to lower GALT activity. The difference was most evident for endometr ioid and clear cell types of ovarian cancer, in which 3.9% of cases were fo und to be homozygous for N314D compared with 0.4% of controls, yielding an odds ratio and 95% confidence interval of 14.17 (2.62-76.60). We conclude t hat, whereas adult consumption of lactose carries no clear risk for the dis ease, certain genetic or biochemical features of galactose metabolism may i nfluence disease risk for particular types of ovarian cancer.