CTSV and squamous cell carcinoma: Elevated expression of CTSV in tumour compared to normal tissue has been observed for squamous cell carcinoma, breast, colorectal and thymic epithelial cancers [2, 8–10], whereas more in depth analysis in hepatocellular and endometrial carcinomas has indicated that elevated CTSV expression is also associated with increasing tumour grade or stage [11, 12].