Decreased expression of chitinases has also been demonstrated during progression of some tumors; for example, AMCase is aberrantly downregulated in gastric adenocarcinoma, liver cancer, renal clear cell carcinoma, and some other malignant tumors, but the specific mechanism is unclear [57,59] the physiological and pathophysiological relevance of chitinases in various organs opens up new possibilities for the treatment of diseases. The gene discussed is CHIA; the disease is clear cell renal carcinoma.