[Gene Mutation and Overexpression of Newly Diagnosed Multiple Myeloma Patients]

To analyze the characteristics of gene mutation and overexpression in newly diagnosed multiple myeloma (NDMM) patients.

Bone marrow cells from 208 NDMM patients were collected and analyzed. The gene mutation of 28 genes and overexpression of 6 genes was detected by DNA sequencing. Chromosome structure abnormalities were detected by fluorescence in situ hybridization (FISH).

Gene mutations were detected in 61 (29.33%) NDMM patients. Some mutations occurred in 5 or more cases, such as NRAS, PRDM1, FAM46C, MYC, CCND1, LTB, DIS3, KRAS, and CRBN. Overexpression of six genes (CCND1, CCND3, BCL-2, CCND2, FGFR3, and MYC) were detected in 83 (39.9%) patients, and cell cycle regulation gene was the most common. Single nucleotide polymorphisms (SNP) changes were detected in 169 (81.25%) patients, the TP53 P72R gene SNP (70.17%) was the most common. Abnormality in chromosome structure was correlated to gene overexpression. Compared to the patients with normal chromosome structure, patients with 14q32 deletion showed higher proportion of CCND1 overexpression. Similarly, patients with 13q14 deletion showed higher proportion of FGFR3 overexpression, whereas patients with 1q21 amplification showed higher proportion of CCND2, BCL-2 and FGFR3 overexpression.

There are multiple gene mutations and overexpression in NDMM. However, there is no dominated single mutation or overexpression of genes. The most common gene mutations are those in the RAS/MAPK pathway and the genes of cyclin family CCND are overexpression.