[Clinical significance of bcl-2 protein expression and classification algorithm in diffuse large B-cell lymphoma].

OBJECTIVE

To investigate the clinical significance of bcl-2 protein expression and three classification algorithms including Hans model, Chan model and Muris model in patients with diffuse large B-cell lymphoma (DLBCL).

METHODS

Two-hundred and thirty-seven cases were collected. Standard two-step EnVision method of immunohistochemical staining was used to assess the expression of Ki-67, CD3, CD45RO, CD20, CD79a, bcl-2, bcl-6, CD10, MUM-1, GCET-1, and FOXP-1. The phenotypic classifications were assessed according to the standard of the three models.

RESULTS

The male (131 cases) to female (106 cases) ratio was about 1.24:1, the average age was 52.6 years. Seventy-five cases (31.6%, 75/237) showed primarily lymph node involvement. Gastrointestinal tract (71 cases) was the most commonly involved extra-nodal organ. All cases expressed one or more pan B cell markers such as CD20 (99.1%, 231/233). All patients with complete clinical follow-up data survived from 1 - 120 months. The expression of bcl-2 protein indicated an adverse prognosis (P = 0.019). Two-hundred and thirty cases were classified according to Hans model, with ninety five GCB cases and one-hundred and thirty five non-GCB cases. Survival analysis showed no difference between GCB and non-GCB subtypes (P = 0.102). According to the Chan's algorithm, sixty eight case of one-hundred and eighty one were belong to GCB group, with one-hundred and thirteen non-GCB cases. GCB subtype showed much better prognosis than non-GCB subtype according to survival analysis (P = 0.031). Additionally, bcl-2 protein expression in non-GCB subtype showed the worst survival. In Muris' model, 154 of 218 cases were classified as Group 1, while 64 cases were classified as Group 2. Group 1 showed better prognosis than Group 2 (P < 0.05).

CONCLUSIONS

Non-GCB group is the more common type of DLBCL in China. High expression of bcl-2 protein is detected in the non-GCB group. Not all subgroups classified with different classification models indicate different prognosis. Bcl-2 expression combined with Chan's algorithm may be the best tool to predict outcome.