SQSTM1 and gastric cancer: Specifically, the expression levels of autophagy marker proteins LC3B and Beclin 1 were significantly reduced, while the expression of equestosome 1 (P62/SQSTM1) was increased in gastric cancer cells (MKN-45) treated with ISO (P62 is a stress-induced intracellular protein, and, as a multifunctional protein for selective autophagy, the expression level of P62 is negatively correlated with autophagic activity) [26].