The Generation and Application of Monoclonal Antibodies to Detect SAPCD2 Expression in Precancerous and Malignant Gastric Lesions

Suppressor APC domain containing 2 (SAPCD2) is involved in cell cycle regulation and its mRNA levels are higher in cancer tissues. But, the function of SAPCD2 in cancer development remains unclear. To generate mouse monoclonal antibodies (mAbs) specific to SAPCD2 and thus clarify the function of SAPCD2 in the development of gastric carcinoma (GC). Purified SAPCD2-GST immunized BALB/c mouse spleen cells were collected and fused with myeloma cells to obtain monoclonal antibody hybridoma. A group of monoclonal antibodies exhibiting high specificity and sensitivity against SAPCD2 has been generated and characterized by IHC, WB, IP, IF, and ELISA. By immunohistochemical analysis, the SAPCD2 expression was evaluated in 228 clinical samples of gastric mucosal lesions, including precancerous lesions and GC samples. We identified a highly specific and sensitive clone of s12 in eukaryotic cells and performed an IHC analysis. We found that 81.3% of 107 GC tissues were SAPCD2-positive, compared with the 26.2% in the matched adjacent normal-appearing tissues (P<0.001). Furthermore, among the 121 gastritis tissues, SAPCD2 was overexpressed in precancerous gastric lesions such as dysplasia (Dys, 78.9%), intestinal metaplasia (IM, 44.7%), and chronic atrophic gastritis (CAG, 6.1%) compared with that in chronic non-atrophic gastritis (CNAG, 3.2%) (P<0.001). The SAPCD2-positivity rate was 81.3% in GC, suggesting that the expression of SAPCD2 increased with the severity of the lesion (P<0.001). In summary, we have described novel monoclonal antibodies against SAPCD2, which are highly expressed in GC tissues and may serve as the basis for an early clinical marker for GC development.