FOXP1 expression predicts polymorphic histology and poor prognosis in gastric mucosa-associated lymphoid tissue lymphomas.

UNLABELLED: RATIONALE/HYPOTHESIS: Forkhead box protein P1 (FOXP1) is one member of the forkhead box protein P (FOXP) subfamily, which are transcription factors that mediate signaling and affect gene regulation, and elevated expression of FOXP1 has been reported to correlate with poor prognosis of diffuse large B-cell lymphoma (DLBCL). Recently, it was also found that FOXP1 expression occurs in mucosa-associated lymphoid tissue (MALT) lymphomas. OBJECTIVE: FOXP1 expression and its relationship to morphology and prognosis in a series of 43 gastric MALT lymphomas were investigated retrospectively. FINDINGS: The FOXP1 nuclear expression (44.2%, 19/43) of tumors between mono- and polymorphic histology (4 of 26 [15.4%] vs. 15 of 17 [88.2%]) was significantly different (p < 0.001). All 14 relapsed tumors after operation featured strong nuclear FOXP1 positivity. A significantly shorter cumulative 10-year survival (52.6%,10/19) was found in high FOXP1 expression patients, compared with patients with negative expression (83.3%, 20/24) (p < 0.01). Also, the cumulative 10-year survival rate (30.8%, 4/13) for stage IIE+IV was significantly shorter than that (83.3%, 25/30) in stage I+II (p < 0.01). Moreover, high FOXP1 expression and advanced stage IIE+IV were independent prognostic factors in multivariate Cox regression analysis. CONCLUSIONS: Our results show that FOXP1 expression is correlated with morphic histology, and FOXP1 and clinical staging appear to be independent prognostic factors in gastric MALT lymphomas.