For example, the higher expression of Xeroderma Pigmentosum A in metastatic effusion is associated with better response to chemotherapy in ovarian cancer patients, paradoxically to the results in primary tumor [5] However, low expression of thymidylate synthase (TS) in metastases is associated with response to 5-FU based therapy in advanced gastric disease [6,7], paralleling to those findings based on primary tumor tissues [8]. The gene discussed is TYMS; the disease is ovarian cancer.