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

Abstract

Background

An association between higher serum calcium (Ca²⁺) levels and breast cancer has been previously reported. However, little is known regarding the relationship between serum Ca²⁺ levels and the expression of Ca²⁺ 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 Ca²⁺ levels between BI-RADS scores (1–3) and BI-RADS scores (4–5) (P = 0.82) was observed. Serum Ca²⁺ levels were similar in women without cancer and women diagnosed with breast cancer (P = 0.94). However, the expression of TRPM7 and TRPC1, but not TRPC3, Ca²⁺ 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 Ca²⁺ channels in infiltrating ductal carcinoma samples with microcalcifications, whereas no change in serum Ca²⁺ levels was observed. Together these data suggest that increased expression of these channels might lead to an increase in intracellular Ca²⁺ levels thereby restoring serum Ca²⁺ levels, but these can contribute to the breast microcalcifications. However, future studies exploring the intracellular Ca²⁺ levels as well as the role of TRPM7 and TRPC1 function according to BI-RADS scores are needed.

Keywords:

• breast microcalcifications
• BI-RADS
• Ca²⁺
• ductal carcinoma
• TRPC1
• TRPM7

Acknowledgments

We thank Ms Mary Kara for assistance with the electronic medical records data. We also thank Dr Donald Sens for providing us with control and breast cancer tissue samples. The lab work was supported by National Institutes of Health Grants DE017102 and 5P20RR017699 (to BBS).

Disclosure

The authors report no conflicts of interest in this work.