CD9 and neoplasm: When the 23 cases with both membranous and cytoplasmic patterns were studied as a separate subgroup, there were significant associations between CD9 expression and tumour grade (P=0.025) (95% CI 11–68), tumour stage (P=0.08) (95% CI 3.5–86) and the occurrence of any failure (P=0.083) (95% CI −1.7–57).