Proto-oncogene amplification and human breast tumor phenotype

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• Proto-oncogene amplification is observed in various cancers.
• Specific proto-oncogenes like c-myc, c-erbB-2, and hst/int-2 are implicated in breast cancer development.

Purpose of the Study:

• To investigate the amplification frequencies of c-myc, c-erbB-2, hst, and int-2 proto-oncogenes in breast tumors.
• To determine the correlation between proto-oncogene amplification and clinicopathological parameters in breast cancer.

Main Methods:

• Analysis of two independent breast tumor series (292 carcinomas).
• Statistical analysis of pooled data from 219 primary breast carcinomas without prior therapy.
• Correlation analysis with estrogen receptor (ER), progesterone receptor (PR) status, tumor grade, and lymph node involvement.

Main Results:

• Amplification frequencies varied between tumor series for c-myc and hst/int-2.
• c-erbB-2 amplification correlated with absence of ER/PR.
• c-myc amplification associated with PR- status and high grade tumors.
• hst/int-2 amplification correlated with PR+ status, ER+ status, low grade, and lymph node involvement.

Conclusions:

• Amplification of c-myc, c-erbB-2, and hst/int-2 proto-oncogenes may represent distinct molecular subsets of breast tumors.
• Proto-oncogene amplification could aid in characterizing new biological subclasses of human breast cancer.