Expression of CD22 in Triple-Negative Breast Cancer: A Novel Prognostic Biomarker and Potential Target for CAR Therapy

Abstract

Triple-negative breast cancer (TNBC) accounts for 15–20% of all breast cancer cases. Due to the lack of expression of well-known molecular targets [estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2)], there is a need for more alternative treatment approaches in TNBC. Chimeric antigen receptor (CAR)-T cell-based immunotherapy treatment is one of the latest treatment technologies with outstanding therapeutic advances in the past decade, especially in the treatment of hematologic malignancies, but the therapeutic effects of CAR-T cells against solid tumors have not yet shown significant clinical benefits. Identification of highly specific CAR-T targets in solid tumors is also crucial for its successful treatment. CD22 is reported to be a multifunctional receptor that is mainly expressed on the surface of mature B-cells (lymphocytes) and is also highly expressed in most B-cell malignancies. This study aimed to investigate the expression of CD22 in TNBC. Bioinformatic analysis was performed to evaluate the expression of CD22 in breast carcinoma and normal tissues. RNA-seq data of normal and breast carcinoma patients were downloaded from The Cancer Genome Atlas (TCGA), and differential gene expression was performed using R language. Additionally, online bioinformatics web tools (GEPIA and TNM plot) were used to evaluate the expression of CD22 in breast carcinoma and normal tissues. Western blot (WB) analysis and immunofluorescence (IF) were performed to characterize the expression of CD22 in TNBC cell lines. Immunohistochemical (IHC) staining was performed on tumor specimens from 97 TNBC patients for CD22 expression. Moreover, statistical analysis was performed to analyze the association of clinical pathological parameters with CD22 expression. Correlation analysis between overall survival data of TNBC patients and CD22 expression was also performed. Differential gene expression analysis of TCGA data revealed that CD22 is among the upregulated differentially expressed genes (DEGs) with high expression in breast cancer, as compared to normal breast tissues. WB and IF analysis revealed high expression of CD22 in TNBC cell lines. IHC results also showed that approximately 62.89% (61/97) of TNBC specimens were stained positive for CD22. Cell membrane expression of CD22 was evident in 23.71% (23/97) of TNBC specimens, and 39.18% (38/97) of TNBC specimens showed cytoplasmic/membrane expression, while 37.11% (36/97) specimens were negative for CD22. Furthermore, significant associations were found between the size of tumors in TNBC patients and CD22 expression, which unveils its potential as a prognostic biomarker. No significant correlation was found between the overall survival of TNBC patients and CD22 expression. In conclusion, we demonstrated for the first time that CD22 is highly expressed in TNBC. Based on our findings, we anticipated that CD22 could be used as a prognostic biomarker in TNBC, and it might be a potential CAR-T target in TNBC for whom few therapeutic options exist. However, more large-scale studies and clinical trials will ensure its potential usefulness as a CAR-T target in TNBC.

Chimeric antigen receptor‐based immunotherapy in breast cancer: Recent progress in China

“…Another potential target CD22 in TNBC is multifunctional receptor primarily expressed on the surface of lymphocytes. Zaib et al 43 identified CD22 as an upregulated gene with high expression in TNBC, suggesting its potential as a target for CAR-T cell treatment (Table 1). 2).…”

Subtype-WGME enables whole-genome-wide multi-omics cancer subtyping

“…Renal cancer patients featured biomarkers such as RPL36A 40 and TACC3, 41 with associations with immune-related pathways and T cell depletion. Within the realm of BRCA patients, GNPNAT1 42 surfaced as an upregulated biomarker associated with proliferation and invasiveness, CD22 43 exhibited heightened expression, correlating with tumor size, DHCR24 44 overexpression was linked to tumor growth promotion, and BUB3 45 was upregulated and negatively correlated with various immune cell types. Furthermore, low PHF2 46 expression was identified as significantly associated with poor prognosis, while FAM83H-AS1 47 and lncRNA-ATB were observed to be overexpressed in sera, demonstrating correlations with tumor metastasis, size, and lymph node metastasis and emphasizing their prognostic rather than diagnostic value.…”

CD22 is a potential target of CAR-NK cell therapy for esophageal squamous cell carcinoma

“…Tuscano et al found high expression of CD22 in lung cancer cells, but was not reproducible by Pop LM [ 20 , 21 ]. What’s more, our group has published another paper to indicate CD22 expression in breast cancer [ 22 ]. Our study found that CD22 was widely expressed in the ESCC cell membrane.…”