BRCA2 and sarcoma: Chemical library screen identified 6-thioguanine as the most potent inhibitor of the survival of BRCA2-deficient human sarcoma U2OS cells and Chinese hamster VS8 fibroblasts. High efficacy of both 6-thioguanine and AG014699 (PARP inhibitor) against BRCA2-deficient xenografted tumors. Comparison of BRCA2-deficient VS8 cells versus isogenic BRCA2-expressing VS8+B2 cells: higher sensitivity to temozolomide, camptothecin and doxorubicin, but lower sensitivity to gemcitabine and paclitaxel.