Breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2) are the most well‑known genes linked to breast cancer and ovarian cancer, which are crucial in DNA repair and transcriptional regulation. The present study aimed to elucidate the expression profiles, mutations and interaction networks of BRCA1 and BRCA2, which may provide insights to reveal the mechanisms of BRCA genes ultimately leading to breast or ovarian tumorigenesis. Bioinformatics analyses were performed in the present study. The mRNA levels of BRCA1 and BRCA2 were evaluated using FIREHOSE analysis, SAGE Genie tools and Oncomine analysis. cBioPortal analysis, and Catalogue Of Somatic Mutations In Cancer analysis were used to examine the BRCA1 and BRCA2 mutations. Kaplan‑Meier Plotter analysis was performed to identify the prognostic roles of BRCA1 and BRCA2 in breast cancer and ovarian cancer. The results of the present study showed that the mRNA expression levels of BRCA1 and BRCA2 were elevated in breast cancer and ovarian cancer tissues, compared with their matched normal tissues. Second, several common mutations of BRCA1 and BRCA2 genes were identified in breast cancer and ovarian cancer. Finally, neurofibromin 1, synaptonemal complex protein 2 and tumor protein 53 were predicted to be involved in the interaction network of BRCA1 and BRCA2 in breast cancer and ovarian cancer. Taken together, these results provide a significant insight into certain mutations and proteins involved in the interaction network of BRCA1 and BRCA2, which may have common roles in breast cancer and ovarian cancer. However, the complex mechanism underlying these observations remains to be fully elucidated, and further investigations are required in the future.