A diagnostic biomarker including a mechanism for determining a patients propensity to develop cancer. A diagnostic kit for determining a patients propensity to develop cancer. A method of predicting both a patients and a populations propensity to develop cancer, by detecting the presence of an H64 and/or P98 allele of galectin-3 from a patients serum sample, and predicting that the patient or population has the propensity to develop cancer based on the presence of the allele. A method of providing prophylactic cancer treatment, by detecting the presence of an H64 and/or P98 allele of galectin-3 from a patients serum sample, predicting that the patient has the propensity to develop cancer based on the presence of the allele, and recommending and providing prophylactic treatment to the patient to reduce their risk of cancer. A prophylactic anticancer treatment and method of preventing onset or further proliferation of cancer.
