Small cell carcinomas of the lung express the Bcl-2 protein.
In our laboratory, we observed that a case of small cell carcinoma of the lung (SCLC) stained with a monoclonal antibody (Dako Corp., Bcl-2-124) against the Bcl-2 protein. To determine how common this reaction was, and whether it was specific for SCLC, we stained formalin-fixed, paraffin-embedded tissues from 23 cases of SCLC and 20 cases of squamous cell carcinoma of the lung for Bcl-2. Fifteen of the 23 SCLC cases stained positively for the Bcl-2 oncogene protein. In contrast, weak staining was observed in only three of the squamous cell carcinomas (chi 2-test; P = 0.001). In addition, four small cell carcinoma cell lines (H69, H146, H209, and WB) were tested by immunohistochemistry and flow cytometry for expression of this protein; all four were positive. In these and three other (H128, H432, and H510) SCLC lines, Northern blots of polyadenylated RNA revealed expression of the 6-kb Bcl-2 mRNA. Moreover, Western blots of extracts from these cell lines revealed the characteristic 26-kd band for Bcl-2 protein. In a single cell line, H82, which has previously been characterized as a variant SCLC, we failed to detect expression of the Bcl-2-specific mRNA and protein. We therefore conclude that most cases of SCLC of the lung express the Bcl-2 oncoprotein, which could play a role in the pathogenesis of this disease.
Department of Pathology, Virginia Commonwealth, University/Medical College of Virginia 23298-0662.
J M
JM
Ben-Ezra
M J
MJ
Kornstein
M M
MM
Grimes
G
G
Krystal
D000911:Antibodies, Monoclonal; D015152:Blotting, Northern; D015153:Blotting, Western; D018288:Carcinoma, Small Cell / Q000378:metabolism* / Q000473:pathology; D015870:Gene Expression; D006801:Humans; D007124:Immunoenzyme Techniques; D008175:Lung Neoplasms / Q000378:metabolism* / Q000473:pathology; D011505:Protein-Tyrosine Kinases / Q000378:metabolism; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger / Q000032:analysis; D014407:Tumor Cells, Cultured
D000911:Antibodies, Monoclonal; D011518:Proto-Oncogene Proteins; D019253:Proto-Oncogene Proteins c-bcl-2; D012333:RNA, Messenger; D011505:Protein-Tyrosine Kinases