Reverse-transcriptase polymerase chain reaction of the maspin gene in the detection of bone marrow breast carcinoma cell contamination

Background. Maspin is a molecular marker used for the detection of contamin ating breast carcinoma (BC) cells in peripheral blood and lymph nodes. Howe ver, its specificity has been questioned recently. The objective of this st udy was to verify the specificity of this marker and to determine the incid ence of positive bone marrow results in patients with BC who are eligible f or high-dose chemotherapy (HDT) both in early and advanced disease stages a nd before and after treatment. Methods. Bone marrow specimens from 41 patients with BC as well as from 35 normal volunteers and 17 patients with hematologic tumors were examined for maspin transcript expression by a modified nested reverse transcriptase-po lymerase chain reaction technique. Results. Maspin transcript was found in all normal and neoplastic breast ti ssues and in none of the 35 normal bone marrow specimens (specificity, 100% ; 95% confidence interval, 90-100%). However, the transcript was found in 4 0% of the bone marrow samples from patients with hematologic malignancies. Thus, this marker appears very specific for discriminating between normal c ontrols and patients with BC, but it cannot be considered disease specific. Among patients with BC, bone marrow was positive for the maspin transcript in 32% of patients with early-stage disease and in 75% of patients with me tastatic disease before chemotherapy. After treatment, in 75% of patients w ith early-stage disease and in 50% of patients with metastatic disease, the bone marrow results became maspin negative. Conclusions. On the basis of the current data, although it is not disease s pecific, maspin is a reliable marker for detecting bone marrow molecular di sease in patients with BC and should be considered for prospective studies as a prognostic indicator and as an assay for monitoring residual disease. Cancer 2001;92:2030-5. (C) 2001 American Cancer Society.