PTEN and pachyonychia congenita: There is a multitude of mechanisms affecting the TME in PC and contributing to immunosuppression, including the inhibition of neoantigen expression, instability of rapid cell division, DNA damage response (DDR) gene defects, decreased human leucocyte antigen (HLA) expression, phosphatase and tensin homolog (PTEN) protein loss, and dysfunction of interferon (IFN) type I signaling [7].