Sensitivity of cancer cells to anti-cancer agents involving measurement of properties of signal transduction factors

A method for the measurement of the sensitivity of a cancer cell to an anti-cancer agent comprises assay of a sample for the mutational status, expression and/or function of a negative signal transduction factor (NSTF), and the mutational status, expression and/or function of a positive signal transduction factor (PSTF), provided that assay of the radiosensitivity of wild-type p53 cancer cells for Raf-1 protein is effected using an antibody thereto. The NSTF may be a factor which inhibits or arrests the cell cycle, causes cells to withdraw from the cell cycle, and/or causes apoptosis or other cell death thereby inhibiting cell division (especially a suppressor), or may be p53, p21 or a PSTF inhibitor (preferably a Raf-1 inhibitor, a cyclin D1 inhibitor or a cyclin-dependent kinase inhibitor). The PSTF may be a factor which stimulates cells to enter the cell cycle, initiates and/or effects DNA synthesis, and/or controls the passage of cells through the cell cycle, preferably an oncogene, a proto-oncogene, a gene which inhibits and/or controls cell cycle division, or a cell surface receptor (especially Raf-1 protein, cyclin D1 protein, or a cyclin-dependent kinase, particularly CDK1 or CDK4). The anti-cancer agent may be ionising radiation, a molecular anti-cancer agent (preferably a chemotherapeutic agent) or a biological cancer therapy agent. Kits, for performing the methods, are described.