Monoclonal antibodies and uses thereof

A method for determining the effectiveness of a treatment regimen for treating cancer by detecting the expression level of an antigen in a biological sample of a patient before and after treatment, the antigen being reactive with the monoclonal antibody 8D11 produced by the mouse hybridoma having ATCC Designation No. PTA-6852 and/or a derivative thereof selected from the group consisting of an Fab, Fab2, single chain antibody, Fv, humanized antibody, and a chimeric antibody, and/or the monoclonal antibody 8A1 produced by the mouse hybridoma having ATCC Designation No. PTA-6853 and/or a derivative thereof selected from the group consisting of an Fab, Fab2, single chain antibody, Fv, humanized antibody, and a chimeric antibody,

• the method comprising:
• determining the level of expression of the antigen in the biological sample obtained before treatment by detecting the binding of the monoclonal antibody 8D11 and/or a derivative thereof and/or the monoclonal antibody 8A1 and/or a derivative thereof to components of the biological sample;
• determining the level of expression of the antigen in the biological sample obtained after treatment by detecting the binding of the monoclonal antibody 8D11 and/or a derivative thereof and/or the monoclonal antibody 8A1 and/or a derivative thereof to components of the biological sample;
• wherein:
• an increase in expression of the antigen after treatment indicates the treatment is not effective;
• and,
• an decrease in expression of the antigen after treatment indicates the treatment is effective.