Breast cancer and family history: levels of lipid-associated sialic acid in plasma and absent family history of breast cancer in women who have breast tumors.

BACKGROUND Breast cancer has a strong genetic component, and at least two breast cancer genes exist. But these genes probably play little role in most breast cancers. Other factors, such as environmental estrogens and diet, may cause the genetic changes involved in the genesis of sporadic breast cancer. A method of observing genetic changes indirectly might be to measure tumor markers known to be associated with breast cancer. METHODS We measured, by biochemical extraction and partition, lipid-associated sialic acid in plasma (LASA-P), a circulating tumor marker, in a group of 239 women with benign or malignant breast tumors. RESULTS The concentration of LASA-P was elevated in women with both benign and malignant tumors and no family history of breast cancer (p = 0.046, one-way ANOVA). Because LASA-P levels rise with age and number of pregnancies, we analyzed our data using multiple linear regression. Benign versus malignant character of the tumor, family history of breast cancer, number of pregnancies, and age were the independent variables. Family history of breast cancer had a significant effect on LASA-P levels (p = 0.0146) independent of the effects of age (p = 0.011), number of pregnancies (0.012), and whether the tumor was benign or malignant (p = 0.31). CONCLUSIONS We hypothesize that elevated LASA-P in women with breast tumors and no family history of breast cancer is a result of the genetic changes occurring in nonfamilial breast cancer. These genetic changes, possibly related to environmental estrogens or other environmental factors, are distinct from the changes due to mutations of BRCA1 or other familial breast cancer genes. Moreover, the elevation of LASA-P suggests that the surface membranes of breast cancer may differ in composition. Further study may lead to exact characterization of the genetic and cell membrane changes associated with familial and nonfamilial breast tumors, and perhaps to better methods of breast cancer prevention and treatment.