CCN2 and hepatocellular carcinoma: However, in HCC cells, ZEB1 is able to directly increase the expression of YAP and activate YAP downstream signaling with the upregulation of genes like AXL receptor tyrosine kinase (AXL), connective tissue growth factor (CTGF) and serum deprivation response (SDPR), which contribute to the malignant phenotype [102].