The result indicated that SPINK1 expression levels correlated with the expression of CES2 and CYP3A5, which are critical drug metabolic genes that have been proved to elicit treatment resistance in many types of cancers [25], in most cases in the treatment non-responsive group (HCC5NR, HCC6NR, and HCC7NR) (Figure 5C). Here, CES2 is linked to cancer.