The Prognostic Value of Inositol Polyphosphate 5-Phosphatase in Cutaneous Squamous Cell Carcinoma.

BACKGROUND: Inositol Phosphate 5-Phosphatase (INPP5A) has been shown to play a role in development and progression of cutaneous squamous cell carcinoma (cSCC). The goal of the current study is to explore the prognostic value of INPP5A expression in cSCC.

METHODS: A total of 189 cases of actinic keratoses and SCCs from 174 patients were identified, clinical and outcome data abstracted, histopathology re-rereviewed, and immunohistochemical (IHC) staining and interpretation was performed for INPP5A.

RESULTS: The majority of tumors (89.4%) had an INPP5A score of 2 or 3. No patients had complete loss of INPP5A. Tumors with INPP5A score of 1 were more likely to be intermediate to high risk (BWH stage T2a and above 85.0% vs 23.7%, p < 0.0001), have a larger diameter (2.4 cm vs. 1.3 cm, p = 0.0004), moderate to poor differentiation (86.7% vs. 17.6%, p < 0.0001), and perineural invasion (37.5% vs. 5.3%, p < 0.0001). INPP5A score of 1 has worse 3-year survival of 42.3% (HR = 2.81, p = 0.0006) and local metastatic rates of 48.0% (HR=4.71, p < 0.0001).

CONCLUSIONS: Low INPP5A scores are predictive of aggressive tumors and may be a useful adjunct to guide clinical management of cSCC.