CA9 and neoplasm: Due to low patient numbers in this sub-cohort, ethnic differences could not be clarified, and no statistically significant differences were observed between the two ethnic groups for IHC staining for either intrinsic hypoxia markers (HIF-1α p = 0.98, GLUT-1 p = 0.69, CA-IX p = 0.61), or microvascular density (p = 0.65), or cytokeratins (CK5/6 p = 0.65) in tumours (Table 3).