A Comparative Study Of Human Primary Gastric, Intestinal Cancer Biological Characteristics Of Diffuse Large B Cell Lymphoma

To compare the clinical features, immunohistochemical classification and genetic alterations of primary gastric diffuse large B-cell lymphoma(PG-DLBCL) with primary intestinal diffuse large B-cell lymphoma(PI-DLBCL). A total of 26 cases of PG-DLBCL and 19 cases of PI-DLBCL were classified into germinal center B-cell-like(GCB) and non-GCB/activated B-cell-like(ABC) subtypes by Hans, Choi and Tally IHC stain algorithms, respectively. Fluorescence in-situ hybridization(FISH) for BCL-2,BCL-6 and MYC gene rearrangements was also performed in these cases. Most(81.3%, 13/16) of PG-DLBCL had stage I/II disease at diagnosis, whereas only 46.7%(7/15) of PI-DLBCL had stage I/II disease at diagnosis. PG-DLBCL tended to present at a earlier stage than PI-DLBCL although the difference did not reached statistically significance(P=0.066). Three algorithms all showed that the frequency of GCB subtype was higher in PG-DLBCL than in PI-DLBCL,which was close to the frequency of non-GCB(or ABC) subgroup in PG-DLBCL but much lower than the frequency of non-GCB(or ABC) subgroup in PI-DLBCL, and the difference reached statistically significance when Tally algorithm was used(P=0.03). No case with BCL-2 gene rearrangement was observed in both PG-DLBCL and PI-DLBCL. BCL-6 gene rearrangement was observed in 22.2%(4/18) of PG-DLBCL,which was slightly lower than that in PI-DLBCL(37.5%,6/16). Only one case(5.9%, 1/17) of PG-DLBCL and one case(6.7%, 1/15) of PI-DLBCL had MYC gene rearrangement. PG DLBCL was clinicalbiologically different from PI-DLBCL, which had earlier stage at diagnosis, higher frequency of GCB subgroup and lower frequency of BCL-6 gene rearrangement than PI-DLBCL.