Conclusion
PTPN1 is overexpressed in HGSC compared to MM effusions, and may be a marker of better chemotherapy response in the former. Whether PTPN1 activation is informative of adverse outcome in MM merits further investigation.
Methods
PTPN1 mRNA expression by quantitative RT-PCR was analysed in 83 high-grade serous carcinoma (HGSC) and 15 malignant mesothelioma (MM) effusions. PTP1B and phospho-PTP1B (pPTP1B) protein expression by immunohistochemistry was analysed in 62 HGSC and 44 MM effusions.
Objective
To analyse the expression and clinical role of the phosphatase PTPN1 (PTP1B) in serous effusions.
Results
PTPN1 mRNA (P = .048), PTP1B protein (P = .047) and pPTP1B protein (P < .001) were overexpressed in HGSC compared to MM effusions. PTPN1 mRNA was additionally overexpressed in post-chemotherapy HGSC effusions compared to chemo-naïve effusions (P = .005). However, pPTP1B protein expression was higher in effusions from patients with FIGO stage III compared to stage IV (P = .006), and higher expressions of both PTPN1 mRNA (P = .041) and PTP1B protein (P = .035) in HGSC effusions were associated with better (complete) chemotherapy response at diagnosis. PTPN1 RNA and protein expression was unrelated to survival in HGSC, whereas a trend for shorter overall survival (P = .06) was found for MM patients whose tumours expressed pPTP1B protein.