PTGS2 and Hand-foot syndrome: Difference between mean COX-2 levels at baseline and 12 weeks was not statistically significantly different among subgroups by gender, treatment arms, occurrence of HFS, severity of HFS (CTCAE grade 0–1 and grade >/=2 HFS, other toxicities (CTCAE grade 1 and >/= grade 2), type of chemotherapy administered (capecitabine monotherapy versus combination), type of primary malignancy (breast versus GI cancers).