BRCA1 and breast cancer: In our in vitro experimental system, re-expression of D-glucuronyl C5-epimerase in breast cancer cells MCF7 significantly (3-8 fold) increased expression level of the breast tumour suppressor genes BRCA1 [22] and SYK (Spleen Tyrosine Kinase) [23] which are known as important inhibitors of breast cancer cell growth and metastasis.