Serum calcium levels, TRPM7, TRPC1, microcalcifications, and breast cancer using breast imaging reporting and data system scores.

Background: An association between higher serum calcium (Ca) levels and breast cancer has been previously reported. However, little is known regarding the relationship between serum Ca levels and the expression of Ca channels in the presence of breast microcalcifications.

Methods: A retrospective analysis of women newly diagnosed with breast microcalcifications was performed based on the Breast Imaging Reporting and Data System (BI-RADS). The expression of TRPC1, TRPC3, and TRPM7 using normal biopsy without microcalcifications (controls) and infiltrating ductal carcinoma with microcalcifications was evaluated.

Results: Data on 138 women were analyzed. Seventy percent of women had a BI-RADS score (1-3) corresponding to benign disease. Seventy-six percent of women with a BI-RADS score (4 or 5) were diagnosed with breast cancer, 56% were cancers in situ, and 93% were infiltrating ductal carcinomas. No difference in the distribution of corrected serum Ca levels between BI-RADS scores (1-3) and BI-RADS scores (4-5) ( = 0.82) was observed. Serum Ca levels were similar in women without cancer and women diagnosed with breast cancer ( = 0.94). However, the expression of TRPM7 and TRPC1, but not TRPC3, Ca channels were increased in infiltrating ductal carcinoma samples with microcalcifications when compared with age-matched controls without calcification or cancer.

Conclusion: We observed an increase in the expression of TRPM7 and TRPC1 Ca channels in infiltrating ductal carcinoma samples with microcalcifications, whereas no change in serum Ca levels was observed. Together these data suggest that increased expression of these channels might lead to an increase in intracellular Ca levels thereby restoring serum Ca levels, but these can contribute to the breast microcalcifications. However, future studies exploring the intracellular Ca levels as well as the role of TRPM7 and TRPC1 function according to BI-RADS scores are needed.