BRCA1 and breast neoplasm: Despite the small numbers, we did not find evidence to support the hypothesis that the tumors would either have LOH of BRCA1 or BRCA2. The TH breast tumor characteristics, however, do appear to be intermediate in phenotype to SH1 and SH2, suggesting some cancers are being driven by inactivation of BRCA1 and some by inactivation of BRCA2. Additional studies that explore other causes of inactivation (e.g., methylation or somatic mutation) are warranted.