An investigation of MYC gene aberration in diffuse large B-cell lymphomas

Objective: This study aims to investigate MYC gene aberration and analyze the correlation of gene aberrations among MYC, BCL-2, and BCL-6 in diffuse large B-cell lymphomas (DLBCL). Methods: Aberrations of MYC, BCL-2, and BCL-6 genes were detected using interphase fluorescence in situ hybridization (FISH), and the protein markers (CD10, BCL-6, MUM1, and Ki67) were stained using immunohistochemistry in the tissue microarrays of 194 DLBCL cases. The correlations among them were analyzed using statistical methods. Results: In 164 of the 194 cases that obtained FISH results of MYC, 38 cases revealed MYC gene aberration (38/164; 23.17%). Of the 38 cases, 9 (9/164; 5.49%) were MYC translocation, and the other 29 (29/164; 17.68%) were MYC gene amplification. No significant difference was observed in the distribution of the aberrations between the cases with germinal central B-cell (GCB) (5/49; 10.20%) and the non-GCB (24/115; 20.87%) subtypes (P=0.187). Of the 159 cases with complete FISH test data, coexistent MYC and BCL-6 gene rearrangements were found in only two "double hit" cases. Aberrations of MYC, BCL-2, and BCL-6 genes or a coexistent rearrangement of the three was not found in the cases. A significantly positive correlation was observed between MYC (28/159, 17.61%) and BCL-2 gene amplification (38/159, 23.90%) (r=0.2916, P=0.000 4). The expression rate of Ki67 (≥90%) was apparently higher in the cases with MYC translocation (5/8, 62.50%) than those without (33/149, 22.15%) (P=0.027 7). High Ki67 expression was found in both "double hit" cases. No significant correlation was found between MYC gene amplification and high Ki67 expression. Conclusion: In addition to gene translocation, gene amplification and other activation pathways of the MYC gene were found in DLBCL. Further studies are needed to elucidate the role of MYC gene aberration in DLBCL.