NONSPECIFIC INCREASED SERUM LEVELS OF SECRETORY COMPONENT IN LUNG-TUMORS - RELATIONSHIP TO THE GENE-EXPRESSION OF THE TRANSMEMBRANE RECEPTOR FORM

Citation
M. Rossel et al., NONSPECIFIC INCREASED SERUM LEVELS OF SECRETORY COMPONENT IN LUNG-TUMORS - RELATIONSHIP TO THE GENE-EXPRESSION OF THE TRANSMEMBRANE RECEPTOR FORM, American journal of respiratory cell and molecular biology, 9(3), 1993, pp. 341-346
Citations number
28
Categorie Soggetti
Cytology & Histology",Biology,"Respiratory System
ISSN journal
10441549
Volume
9
Issue
3
Year of publication
1993
Pages
341 - 346
Database
ISI
SICI code
1044-1549(1993)9:3<341:NISLOS>2.0.ZU;2-P
Abstract
Polymeric immunoglobulin receptor (pIg-R) is synthesized by epithelial cells lining the bronchial mucosa. It is released in secretions as fr ee secretory component (SC) or bound to Ig as secretory Ig (S-IgA and S-IgM). To evaluate the usefulness of SC and pIg-R expression as tumor markers, we measured SC and secretory Ig, using enzyme-linked immunos orbent assay, in the serum of 45 patients with lung carcinomas, in the serum of 10 patients with non-neoplastic diseases, and in the serum o f 45 control subjects. We also studied the immunohistochemical express ion of pIg-R and its mRNA in tumors from 20 out of the 45 patients. Se rum levels of SC and S-IgA were similarly and significantly elevated i n patients with lung cancer (squamous cell carcinoma [25 cases], small cell carcinoma [7 cases], adenocarcinoma [13 cases]) and with non-neo plastic diseases, as compared with control subject levels (P < 0.001). The highest SC levels were found in patients with adenocarcinoma alth ough the mean SC level was not different from other pathologic conditi ons. pIg-R was usually not detected in the cells of small cell carcino ma or of squamous cell carcinoma, whereas it was found in the cells of five adenocarcinomas and in the two in situ carcinomas under study. T he specific mRNA analysis usually agreed with the immunolocalization o f pIg-R. A single band at 3.8 kb was detected in the positive tumor ti ssues and in normal lung tissues. However, the signal was weak in one case of squamous carcinoma and stronger in two out of three adenocarci nomas, than in normal tissues. Seven transplanted tumors, developed in nude mice from the metastases of adenocarcinoma (three cases), small cell carcinoma (one case), and squamous cell carcinoma (three cases), were negative for pIg-R and its mRNA expression. We concluded that hig h serum levels of SC were not specific for lung tumors and that SC was secreted mainly by normal lung tissue in contact with tumor cells, ex cept in adenocarcinoma where tumor cells synthesized pIg-R. High pIg-R mRNA levels and pIg-R expression could be considered characteristic f eatures of adenocarcinomas. The preserved expression of both pIg-R and its mRNA in cells of in situ squamous cell carcinoma, and expression of a weak expression of the pIg-R RNA only, in some of the squamous ce ll carcinomas, could indicate intermediate stages of cell differentiat ion.