PTEN and neoplasm: The non-infiltrated tumor phenotype has also been correlated in many different tumor types with the loss of the oncogene phosphatase and tensin homolog (PTEN), which results in constitutive activation of the phospho-inositol-3-kinase (PI3K), leading to an enhanced transcription of suppressive factors that can impair DC function and priming of an immune response [31,32].