Abstract: This invention relates to a quantitative method for determining whether a human subject has an impaired DNA mismatch repair function; providing a diagnostic sample taken from said human and producing a nuclear extract from said sample; providing MMR proficient and MMR deficient nuclear extracts as positive and negative controls, respectively; combining each nuclear extract with at least one mismatch bearing substrate DNA molecule; performing a mismatch repair assay; and determining whether said sample nuclear extract is capable of repairing said substrate DNA molecule; wherein said sample comprises normal, non-malignant constitutive cells, such as fibroblasts. The invention further relates to a kit providing necessary reagents for use in said method.

Abstract: This invention relates to a quantitative method for determining whether a human subject has an impaired DNA mismatch repair function; providing a diagnostic sample taken from said human and producing a nuclear extract from said sample; providing MMR proficient and MMR deficient nuclear extracts as positive and negative controls, respectively; combining each nuclear extract with at least one mismatch bearing substrate DNA molecule; performing a mismatch repair assay; and determining whether said sample nuclear extract is capable of repairing said substrate DNA molecule; wherein said sample comprises normal, non-malignant constitutive cells, such as fibroblasts. The invention further relates to a kit providing necessary reagents for use in said method.