Systemic chemotherapy induces microsatellite instability in the peripheral blood mononuclear cells of breast cancer patients.

Introduction: Systemic chemotherapy is an important part of treatment for breast cancer. We conducted the present study to evaluate whether systemic chemotherapy could produce microsatellite instability (MSI) in the peripheral blood mononuclear cell fraction of breast cancer patients.

Methods: We studied 119 sequential blood samples from 30 previously untreated breast cancer patients before, during and after chemotherapy.

Peripheral blood c-erbB-2 expression by reverse transcriptase-polymerase chain reaction in breast cancer patients receiving chemotherapy.

Minimal residual disease (MRD) evaluation in breast cancer patients is a promising tool to improve current staging procedures. In a previous work employing a CK-19-based reverse transcriptase-polymerase chain reaction (RT-PCR) technique for MRD detection, we identified a group of women who exhibited persistent negativity for this assay and for whom this technique was considered noninformative. In order to improve the yield of MRD detection in these patients, we evaluated the usefulness of RT-PCR detection of c-erbB-2 expression.