47-mG 2a : A Mouse IgG 2a -Type of PcMab-47 Useful for Detecting Podocalyxin in Esophageal Cancers by Immunohistochemistry

Abstract

Esophageal cancer is one of the highly malignant cancers. It comprises two of the most common histological tumor types: squamous cell carcinoma (SCC) and adenocarcinoma. SCC accounts for about 90% of esophageal cancers. Despite developments in treatment strategies, the prognosis and survival rate remain poor. Podocalyxin (PODXL) is a highly glycosylated type-I transmembrane protein. It is expressed in normal tissues such as kidney, heart, breast, and pancreas. Upregulation of PODXL correlates with tumor progression, invasion, and metastasis. Therefore, this glycoprotein could be a potential biomarker for predicting the prognosis of some cancers, for instance, brain, colorectal, oral, lung, bladder, prostate, and ovarian cancers. We previously developed a specific and sensitive anti-PODXL monoclonal antibody (mAb), PcMab-47 (mouse IgG₁, kappa) and its mouse IgG_2a-type (47-mG_2a). We showed their utility in immunohistochemical analysis of oral cancers. Herein, we demonstrate that PcMab-47 and 47-mG_2a can also be used to detect esophageal squamous cell carcinoma (ESCC) with this technique. These two antibodies, respectively, stained 123/130 (94.6%) and 127/130 (97.7%) ESCC cases, indicating that they can detect PODXL with high sensitivity in this carcinoma. Of more than 3+ cases, 47-mG_2a was more effective than PcMab-47, respectively, staining 56/127 (44.1%) and 41/123 (33.3%). Therefore, 47-mG_2a can be used for the detection of PODXL in ESCC using immunohistochemical analysis.