Report of Breas t and Thyroi d Cancer Prone Fami l i es

Abstract

Thyroid cancer is often found in tumor spectra of familial breast cancer and occur frequently in primary multiple canceres including breast cancer. We herein report five breast-thyroid cancer prone families. Genetic testing was performed in only one family, then genetic relation to thyroid cancer was obscure. According to our clinical observation, there are two types of breast-thyroid cancer prone families: 1) thyroid cancer occurring in BRCA linked hereditary breast cancer families, and 2) thyroid and breast cancer were clustered in families. Taking a family history in clinical practice is important to reveal cancer prone families.