Expression of c-myc in progenitor cells of the bronchopulmonary epithelium and in a large number of non-small cell lung cancers.
We performed in situ hybridization for c-myc, N-myc, and L-myc mRNA expression using 35S-labeled cRNA probes on frozen sections of 19 pairs of non-small cell lung cancers (NSCLC) and the surrounding non-neoplastic lung tissue. In non-neoplastic lung, c-myc expression was strongest in bronchial epithelium basal cells and hyperplastic alveolar type II pneumocytes, which are potential progenitor cells for bronchopulmonary epithelium and their tumors. In contrast, N-myc and L-myc mRNAs were not detected in non-neoplastic lung. In studies of freshly resected primary tumors, expression of c-myc was detected in 11 of 19 NSCLC (with the highest levels in squamous cell carcinomas), two of which also expressed L-myc, while N-myc expression was never detected. Levels of c-myc expression in tumors were significantly higher than in non-neoplastic lung samples. We conclude that: (1) c-myc expression in non-neoplastic lung tissues is highest in bronchial basal cells and hyperplastic type II cells, and (2) in NSCLC, overexpression of the myc-proto-oncogene is common.
Navy Medical Oncology Branch, Bethesda, Maryland.
J L
JL
Broers
J
J
Viallet
S M
SM
Jensen
H
H
Pass
W D
WD
Travis
J D
JD
Minna
R I
RI
Linnoila
D015152:Blotting, Northern; D001980:Bronchi / Q000166:cytology / Q000378:metabolism*; D002289:Carcinoma, Non-Small-Cell Lung / Q000378:metabolism*; D004847:Epithelial Cells; D004848:Epithelium / Q000378:metabolism; D015870:Gene Expression; D016259:Genes, myc; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D019394:Ki-67 Antigen; D008175:Lung Neoplasms / Q000378:metabolism*; D005810:Multigene Family; D009363:Neoplasm Proteins / Q000096:biosynthesis; D009687:Nuclear Proteins / Q000096:biosynthesis; D000090063:Proto-Oncogene Mas; D013234:Stem Cells / Q000378:metabolism*
D019394:Ki-67 Antigen; C000715470:MAS1 protein, human; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; D000090063:Proto-Oncogene Mas