Increased chromobox (CBX) family mRNA and protein expression was associated with poor prognosis in patients with diffuse large B-cell lymphoma (DLBCL), according to a study published in BMC Cancer.

Kaplan-Meier survival analysis found that high expression of CBX2, CBX3, CBX5, and CBX6 in tumor tissue was associated with worse overall survival in patients with all P <0.05 and hazard ratios (HRs) between 1.4 and 1.9. In contrast, increased expression of CBX1 was correlated with a better prognosis (HR 0.63; P =0.0043). Multivariate Cox regression analysis found that CBX3 alone was an independent prognostic indicator (HR 1.81; P =0.00).

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“We provided a detailed analysis of the relationship between the CBX family and the prognosis of DLBCL,” the authors wrote.

The expression of CBX1/2/3/5/6/8 mRNA and protein was higher in patients with DLBCL than in control group tissues based on data obtained from the Gene Expression Profiling Interactive Analysis, Oncomine, and Cancer Cell Line Encyclopedia databases. 

A comparison of immunohistochemistry staining images from the Human Protein Atlas confirmed higher expression of CBX1/2/3/5/6 in patients with DLBCL compared to controls, but CBX8 levels were low in both groups. The results of the database analysis showing increased expression of CBX1/2/3/5/6 in DLBCL compared to controls were verified through in-house immunohistochemistry of 18 DLBCL samples and 18 nontumor lymph nodes (all P <0.0001).

Further analysis found that the expression levels of CBX1/5/6 were all significantly positively correlated with the infiltration of various immune cells within the tumor microenvironment, including neutrophils, memory cells, and macrophages.

Drug sensitivity analysis found that cells overexpressing CBX1/2/3/5/6/8 were sensitive to certain small-molecule drugs. However, cells with high levels of CBX1 expression tended to have an increased resistance to most of the drugs tested, and CBX2 and CBX5 were resistant to some and sensitive to others.

Reference

Zhou F, Chen L, Lu P, et al. An integrative bioinformatics investigation and experimental validation of chromobox family in diffuse large B-cell lymphoma. BMC Cancer. Published online July 10, 2023. doi:10.1186/s12885-023-11108-6