GLS and cancer: GLS1, as the key enzyme in glutamine metabolism, is a promising and potential therapeutic target giving the facts that: a) glutamine is unnecessary for normal cells while essential for cancer cells in vivo and vitro [10], b) activity or expression of GLS1 was activated or increased in several tumor origins and inhibition of activity or depression of GLS1 expression resulted in decreased proliferation rate in cancer cells [12, 14, 40] and c) oncogenes and tumor suppressor genes are involved in regulation of GLS1 [13, 48, 49].