Mutation in exon 2 of the c-myc gene was present in 2 of 20 (10%) patients with low-grade MALT lymphoma, in 1 of 7 (14%) patients with high-grade MALT lymphoma, and none of 10 patients with DLL.
To further investigate whether ASHM also occurs in mucosa-associated lymphoid tissue type (MALT) lymphoma, we studied the mutation profile of PIM1, PAX5, RhoH/TTF, and c-MYC in 17 MALT lymphomas and 17 extranodal diffuse large B-cell lymphomas (DLBCLs) still exhibiting a low-grade MALT lymphoma component (transformed MALT lymphoma).
Translocations involving IGH were detected in 36 (32%) of 111 cases; their partner genes included BCL6 (n = 10), c-MYC (n = 5), and FOXP1 (n = 3) but remained unknown in the remaining 18 cases. t(14;18)/IGH-BCL2, t(14;18)/IGH-MALT1, and t(1;14)/BCL10-IGH were not detected in any case. t(11;18)/API2-MALT1 was detected in none of the cases, except for one case of DLBCL with MALT lymphoma, which showed positive signals only in MALT lymphoma cells.