THBS1 and melanoma: Overexpression of THBS1 (TSP1) was detected in breast carcinoma and melanoma cells by interferon (IFN)-gamma-differentiated U937 cells in vitro via the release of reactive oxygen species.30 Finally, the expression of SERP1 was suppressed in papillary thyroid cancer.31 However, SERP1 and POLR2 have not yet been identified in breast cancer cells.