Authors: Shreeja Mehrotra, Susrutha K. Wickremesekera, Helen D. Brasch, Bede Van Schaijik, Reginald W. Marsh, Swee T. Tan and Tinte Itinteang
Colorectal cancer is the third most common cancer worldwide with an approximately 50% mortality rate. It metastasises with the liver being the most common secondary site. Up to 70% of the deaths associated with colorectal cancer manifest liver metastasis. Although surgery of the liver has the best outcome for these patients, a procedure following diagnosis is possible in only about 20% of cases.
Three sub-populations of cancer stem cells have been characterised in liver metastasis. These stem cells are thought to be responsible for generating the tumour, tumour differentiation, maintenance, spread and relapse. Components of the renin-angiotensin system are expressed in cancer stem cells. The cathepsin enzymes (B, D and G) digest proteins and so can facilitate the invasion and metastasis of colorectal cancer to the liver. The paper reports the detection of these three enzymes in the stem cells found in liver cancer.