PTGFRN and neoplasm: We studied 55 hLT biopsies (including 17 cases of secondary hLT) for CD9 and CD9P-1 gene expression, using the CD9 index (CD9 mRNA level in tumour core relative to CD9 mRNA in surrounding tissues) and the CD9P-1 index (CD9P-1 mRNA level in tumour core relative to CD9P-1 mRNA in surrounding tissues).