SQSTM1 and cancer: Importantly, p62-deficient cancer cells, such as p62-knockdown (p62KD) SK-HEP-1, p62KD MDA-MB-231, and p62-knockout (p62KO) A549 cells, showed increased activation of autophagy induced by TLR4 stimulation, suggesting that p62 negatively regulates autophagy activation.