A tumor suppressor function for the lipid phosphatase INPP4B in melanocytic neoplasms.

The phosphoinositide-3 kinase (PI3K) pathway is deregulated in a significant proportion of melanomas, and PI3K pathway activation in combination with constitutively active mitogen-activated protein kinase signaling shows synergistic effects in the process of melanoma tumorigenesis. Recently, a tumor suppressor function for the lipid phosphatase inositol polyphosphate 4-phosphatase type II (INPP4B) has been described in breast and prostate cancers, with impact on PI3K signaling output. Given the importance of PI3K pathway activity for melanoma formation and growth, we aimed to assess the role of INPP4B in melanocytic tumors.