To further investigate the involvement of specific BRCA1 functional domains in the regulation of the PIN1-LYN axis, and the possibility that different clinically relevant BRCA1 mutants may have different effects on this axis, we re-expressed either the wild-type BRCA1 or clinically relevant BRCA1 missense mutants (C61G in the RING domain, L1407P in the CC motif, and A1708E in the BRCT domain) (Anantha et al., 2017) in the HCC1937 human BRCA1-deficient breast cancer cell line. This evidence concerns the gene PIN1 and breast cancer.