Amplification of c-myc gene and overexpression of c-Myc protein in breast cancer and adjacent non-neoplastic tissue.
BACKGROUND
Deregulated c-Myc expression and alterations of c-myc oncogene have been reported to play an important role in breast cancer tumorigenesis. We examined the relationship between c-Myc protein level, amplification of c-myc oncogene and commonly used clinical and pathologic factors.


METHODS
The studies were conducted on 94 ductal and lobular cancers. Amplification of c-Myc was assessed by the semiquantitative multiplex PCR assay. The amount of c-Myc protein was estimated by the densitometry analysis of Western blots.


RESULTS
Amplification of c-Myc was found in 21% of examined cancers. There was no association of c-myc amplification with established risk factors. Overexpression of c-Myc protein without c-myc amplification was associated with negative status of axillary lymph node. The size of lobular carcinoma displaying overexpression of c-Myc and the normal copy number of c-myc gene was significantly smaller than the size of tumor with elevated c-Myc and amplification of c-myc gene (p < 0.01). Within tumors displaying overexpression of c-Myc protein and c-myc gene amplification the size of ductal carcinoma was smaller than the size of lobular carcinoma (p < 0.007).


CONCLUSIONS
Data presented in this study suggest that alterations of c-myc gene and c-Myc protein level might be related to breast cancer progression. The prognostic utility of elevated level of c-Myc protein associated with normal status of c-myc gene for patients with lobular carcinoma requires further studies.
Chrzan
P
P
Department of Molecular Medicine, Medical University of Gdansk 80-211, Gdansk, Poland.
Skokowski
J
J
Karmolinski
A
A
Pawelczyk
T
T
D001940:Breast / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism; D005260:Female; D005784:Gene Amplification; D006801:Humans; D008198:Lymph Nodes / Q000378:metabolism; D008875:Middle Aged; D016271:Proto-Oncogene Proteins c-myc / Q000235:genetics* / Q000378:metabolism
D016271:Proto-Oncogene Proteins c-myc