Th17 T<sub>EM</sub> cells (expressing <i>IL17A, IL17F, RORC</i>, and <i>STAT3</i>) displayed a higher pathogenic/cytotoxic (<i>IL23R, IL18RAP</i>, and <i>GZMB, CD160, PRF1</i>) gene signature in CD relative to UC, while non-pathogenic/regulatory genes (<i>IL9, FOXP3, CTLA4</i>) were more elevated in UC.
In general, genes encoding cytokines are genetically polymorphic and polymorphisms in genes IL23R el IL17F were shown associated with susceptibility to Crohn's disease and ulcerative colitis which in their turn are considered as risk factors for developing colorectal cancer (CRC).
The IL17F (rs763780, 7488T/C) variant was associated with an increased risk for the development of CD, and affected some clinical features of UC and CD.