Prognostic value of immunohistochemical algorithms in gastrointestinal diffuse large B-cell lymphoma

Abstract

Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous clinicopathological entity, and its molecular classification into germinal center B cell-like (GCB) and activated B cell-like (ABC) subtypes using gene expression profile analysis has been shown to have prognostic significance. Recent attempts have been made to find an association between immunohistochemical findings and molecular subgroup, although the clinical utility of immunohistochemical classification remains uncertain. The clinicopathological features and follow-up data of 68 cases of surgically resected gastrointestinal DLBCL were analyzed. Using the immunohistochemical findings on tissue microarray, the cases were categorized into GCB and non-GCB subtypes according to the algorithms proposed by Hans, Muris, Choi, and Tally. The median patient age was 56 years (range, 26-77 years). Of the 68 cases included, 39.7% (27/68) involved the stomach, and 60.3% (41/68) involved the intestines. The GCB and non-GCB groups sorted according to Hans, Choi, and Tally algorithms, but not the Muris algorithm, were closely concordant (Hans vs. Choi, κ=0.775, P<0.001; Hans vs. Tally, κ=0.724, P<0.001; Choi vs. Tally, κ=0.528, P<0.001). However, there was no prognostic difference between the GCB and non-GCB subtypes, regardless of the algorithm used. On univariate survival analyses, international prognostic index risk group and depth of tumor invasion both had prognostic significance. The Hans, Choi, and Tally algorithms might represent identical DLBCL subgroups, but this grouping did not correlate with prognosis. Further studies may delineate the association between immunohistochemical subgroups and prognosis.