Production of Monoclonal antibodies to membrane components of human colorectal cancer HCT-116 cell line for diagnostic purposes

Colorectal cancer (CRC) is the second leading cause of cancer-related death worldwide. The survival rate of people diagnosed in the early stages of disease is 92 % whereas; less than 11 % of patients survive if reached stage IV. Moreover, only 24 % of cases are diagnosed during stage I. Thus, the early diagnosis of the CRC will save many lives, reduce suffering of patients. Biomarkers that are in use for the diagnosis of CRC such as Carcinoembryonic Antigen (CEA), Carbohydrate Antigen (CA 19–9) suffer from low sensitivity, expressed in other neoplasms, and not expressed in early stages of cancer. This study aims to find a highly sensitive and specific biomarker for early detection of CRC. Hybridoma clones were established by fusing spleen cells from mice hyperimmunized with human cell membrane homogenate of HCT116 with murine myeloma cells X63Ag8. One clone was selected after fusion and designated as D2C5. Isotyping of secretory antibody revealed an IgG1 kappa light chain and was reactive to a protein with molecular weight about 55 kDa using immunoblot. In situ reactivity of the D2C5 showed homogenous and cytoplasmic pattern staining in stage IV and III, discrete and heterogeneous pattern was seen in stage II samples. Moreover, nuclear staining pattern was seen in one slide of stage II samples. In addition, mucinous type was detected. Low peripheral staining was observed in normal colon tissue. These observations suggest the localization of the target protein in the cytoplasm of epithelial cells with high expression in more advanced cases, suggesting a cytokeratin pattern of staining.