Preclinical feasibility study of NMP179, a nuclear matrix protein marker for cervical dysplasia.

OBJECTIVE: To evaluate, in a preclinical feasibility study, the efficacy of NMP179, a monoclonal antibody recognizing a cervical tumor-associated nuclear matrix antigen, for the early detection of high and low grade cervical intraepithelial neoplasia. STUDY DESIGN: In a blind study involving two clinical sites, NMP179 immunocytochemical staining data from 261 cervicovaginal Thin-Prep specimens were evaluated. Assay sensitivity and specificity were calculated based upon a positive threshold of > 10 immunostained cells per case, using cytologic diagnosis as an end point. RESULTS: Based upon the examination of squamous epithelial cells, NMP179 detected 96.7% of cases with cytologically diagnosed high grade squamous intraepithelial lesions (HSIL) and 70.5% of low grade squamous intraepithelial lesions. The antibody also reacted with 29.6% of normal (within normal limits or benign cellular changes) smears. CONCLUSION: The NMP179 assay detected HSIL with very high accuracy (96.7%). The assay was 79.3% sensitive for the detection of low and high grade cervical intraepithelial neoplasia (grades 1-3), with a specificity of 70.4%. NMP179 may be an effective marker for the early detection of preneoplastic squamous intraepithelial lesions of the cervix and may be useful as an adjunctive tool for better management of cervical intraepithelial neoplasia.

Preliminary immunohistochemical characterization of a monoclonal antibody (PRO:4-216) prepared from human prostate cancer nuclear matrix proteins.

OBJECTIVES: A nuclear matrix protein (PC-1) was previously identified and reported to be present only in human prostate cancer but absent in tissue from the same prostate containing either benign prostatic hyperplasia (BPH) or normal prostate tissue. The PC-1 protein was identified by high resolution two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) and exhibited a molecular mass of 56 kDa and an isoelectric point of 6.58. This work investigates the immunohistochemical characterization of PRO:4-216, a monoclonal antibody to PC-1. METHODS: Areas of the 2D-PAGE gels containing the human prostate cancer nuclear matrix proteins near PC-1 were isolated, eluted, and injected into mice to develop monoclonal antibodies. Antibodies were screened by immunofluorescence for nuclear reactivity to a human prostate cancer cell line (LnCaP) and by 1D and 2D Western blots for reactivity with prostate cancer nuclear matrix proteins. Monoclonal antibodies from the selected clones were affinity purified. The monoclonal antibody PRO:4-216 was used to analyze frozen tissue from 20 cancerous, 22 BPH, and 22 normal regions from fresh human prostate specimens. Tissue sections were analyzed for their immunohistochemical (IHC) (horseradish peroxidase) staining. RESULTS: Using a reference value for positive staining at an IHC score of greater than 50, 85% (17 of 20) of the cancerous, 5% (1 of 22) of the BPH, and 9% (2 of 22) of the normal prostate tissues stained positive. The one BPH and two normal tissues that stained positive were taken from prostates in which the adjacent cancerous tissue also demonstrated high IHC scores (greater than 225). CONCLUSIONS: These data demonstrate nuclear reactivity on fresh frozen human prostate cancer tissue for the monoclonal antibody PRO:4-216. PRO:4-216 may aid in distinguishing normal prostate and BPH from cancerous tissue.