Immunoperoxidase staining of tumors by an antibody to Xenopus pNiXa.

pNiXa, a serpin from oocytes and embryos of Xenopus laevis, was tested as a tumor marker in human and rodent tissues. A peptide corresponding to the histidine-rich domain of pNiXa was conjugated and administered to rabbits to produce a polyclonal antibody, which was purified by antigen-affinity and used for immunoperoxidase staining of formalin-fixed, paraffin-embedded tissue sections. Staining with pNiXa-antibody was positive in 23/187 human tumors (12 percent) and negative in 119 specimens of normal human tissues. Positive reactions were more frequent in liver (38 percent) and colon (34 percent) tumors than breast (18 percent), prostate (9 percent), mesothelioma (20 percent) or lung (0 percent) tumors. Staining was negative in human tumors from other sites. Rodent tumors and preneoplastic foci induced by chemical carcinogens were surveyed for staining with pNiXa-antibody. Staining was positive in 10/10 hepatic lesions (hepatocellular foci, adenomas, carcinomas) induced in hybrid D2B6F1 mice by diethylnitrosamine and phenobarbital, whereas murine mammary tumors and thyroid, pituitary, renal, and colon tumors of F-344/CNr rats were negative. Thus, immunostaining with pNiXa-antibody identifies a subset of human and murine tumors; further studies are needed to determine if reactivity of pNiXa-antibody has diagnostic or prognostic significance.

DNA ploidy in breast lesions. A comparative study using two commercial image analysis systems and flow cytometry.

DNA ploidy determinations on a series of 24 breast specimens were performed independently utilizing flow cytometry (FCM) and two separate commercially available computerized image analysis systems for image cytometry (ICM). The tissues analyzed were obtained from 20 carcinomas, 2 benign neoplasms and 2 benign reductive procedures. The results showed a close correlation between the DNA indices (DIs) obtained by all methods in 14 of the 24 cases. In four cases, all methods showed aneuploid peaks, but with differing DIs. In six cases (two benign and four malignant) FCM showed diploidy while ICM showed peridiploid cell populations. The results obtained with the two image analysis systems were in agreement for 20 of the 24 cases. ICM is an acceptable alternative to FCM for reproducible ploidy analysis. ICM-based measurements have the advantage of the visual discrimination of abnormal cells and therefore may have a greater sensitivity in identifying small aneuploid populations. Populations with DIs in the range of 1.0 to 1.3 need to be assessed carefully in ICM-based determinations due to the potential that these "aneuploid" peaks may represent shifted diploid populations.