PTEN and neoplasm: Interestingly, both the constitutive activation of these receptors, as well as activating mutations of downstream elements in these pathways (Ras, PI3-K, AKT, and PDK-1) or mutations that inactivate negative regulators (TSC1/2, LKB1, and PTEN) are common in the development of cancer [36, 38, 47, 48, 50], suggesting that inhibition of autophagy likely contributes to the onset to tumor development.