Reagents, methods, and kits for the classification of cancer that comprise or employ antibodies that bind specific regions of CD43. One method includes contacting tissue with an antibody capable of specifically binding the cytoplasmic tail of CD43, contacting the tissue with an antibody capable of specifically binding the extracellular domain of CD43, and resolving cellular localization of any binding to the tissue with the antibody capable of specifically binding the cytoplasmic tail of CD43 and the antibody capable of specifically binding the extracellular domain of CD43. The binding patterns of the antibodies can be used to characterize cancer as more aggressive or less aggressive and can distinguish small cell lung cancer from non-small cell lung cancer. The cancer may therefore be treated in accordance of the characterization.