CYP2C8 and neoplasm: However, carrying at least one copy of CYP2C8*4 was associated with a significantly lower frequency of axillary lymph node involvement (21% versus 38%; P=0.002) in spite of a lower frequency of PR-positive tumours (57% versus 71%; P=0.012) and similar tumour sizes compared with patients without this SNP (Table 4).