The mixed template assay showed 96% concordance between calculated and measured gene copy number. int-2 gene and c-erbB2 amplification were both found in 24% of the tumors.
Survival analyses within the RR group, however, demonstrated significantly shorter survival time among cases with than without ERBB2 amplification (P = 0.018, median survival 16 vs 25 months), or ERBB2 expression (P = 0.019, median survival 15 vs 25 months), but not INT2 amplification.
Relapse occurred more frequently in patients with c-erbB-2 gene amplification (relapse in 33.3% of the patients with c-erbB-2 amplification compared to 20.7% in the non-amplified group), but the difference was not statistically significant, int-2 amplification was not associated with increased risk of relapse, whereas the prognostic value of the c-myc amplification could not be evaluated.
Amplification of the int-2 oncogene was measured in a series of breast tumours and related to amplification of the c-myc and c-erbB-2 oncogenes, histopathological features and relapse-free and overall survival. int-2 was amplified in 11%, c-myc in 20% and c-erbB-2 in 27% of the tumours assessed. int-2 amplification was associated with large tumour size (p < 0.05) and reduced relapse-free (p < 0.05) and overall (p < 0.0005) survival. c-myc amplification was associated with poor tumour differentiation (p < 0.05) but had no association with prognosis. c-erbB-2 amplification was associated with low levels of expression of oestrogen receptor mRNA (p < 0.05), poor tumour differentiation (p < 0.05) and shortened relapse-free (p < 0.0001) and overall survival (p < 0.0001).
Amplification of c-erbB-2, c-myc, and int-2, and expression of RB, p53(mutant), and NDP kinase were determined in 77 primary breast cancer specimens. nm23-H1 allelic loss was also studied. c-erbB-2 and c-myc amplification, loss of RB expression, p53(mutant) expression, and nm23-H1 allelic loss were also found in non-invasive carcinoma. int-2 amplification was significantly correlated with lymph node status (P = 0.02) and a significant association was found between p53(mutant) expression and tumor size (P = 0.04). c-erbB-2 amplification was strongly associated with disease-free and overall survival in multivariate analysis (P = 0.002).
HER2/neu amplification was negatively correlated with oestrogen receptor (ER) and progesterone receptor (PR) status (P less than 0.0001; for both), c-myc amplification was more prevalent in the PR-negative subpopulation (P less than 0.05) and int-2/bcl-1 amplification was positively correlated with ER status (P less than 0.001).