p185 overexpression in 220 samples of breast cancer undergoing primary surgery: comparison with c-erbB-2 gene amplification

Her-2/neu gene amplification and its correlation with other prognostic factors in Iranian breast cancer patients

BACKGROUND

Breast cancer is one of the most common diseases in females, arising from overexpression of a variety of oncogenes like HER2/neu. The amplification rate of this gene is variable in different breast cancer patients. In this study, the amplification of the HER2/neu oncogene was distinguished in breast cancer patients and its correlation with prognostic factors. Also, the simultaneous effect of prognostic factors on the occurrence of a specific prognostic factor was investigated.

MATERIALS AND METHODS

The multiplex PCR technique was used to assay the amplification of the HER2/neu oncogene in breast cancer patients. After extracting DNA from 100 tumor tissue and 8 normal breast tissue samples, the amplification of the HER2/neu gene was distinguished by the co-amplification of a single-copy reference gene, γ-IFN, and the target gene HER2/neu in the PCR reaction and using the Gel analyzer software. SPSS 23 and STATA 9.1 software were used for statistical analysis.

RESULTS

The HER2/neu gene was amplification in 30% of the tumor samples. The statistical analysis showed a statistically significant relationship between HER2/neu gene amplification and progesterone receptors. Amplification of the HER2/neu gene significantly increases the chance of lymph node involvement. Also, the amplification of this gene in tumors with histological grade II tissue is more than grade I.

CONCLUSION

The amplification of the HER2/neu gene can be used as an independent prognostic factor in predicting lymph node involvement and histological grade in breast cancer patients.

Amplification of the BP1 homeobox gene in breast cancer

The homeobox gene BP1 is expressed in over 80% of breast cancers and is associated with tumor progression and invasion. However, the mechanism of BP1 activation in these tumors remains unknown. Therefore our aim in this study is to assess the amplification status of the BP1 gene in breast cancer and to determine whether BP1 protein expression is caused by gene amplification in these tumors. BP1 amplification and expression were assessed in 36 samples. Twenty primary breast tumors (PBT) and 14 sentinel lymph node (SLN) metastases were analyzed using fluorescence in situ hybridization (FISH) and immunohistochemistry (IHC), respectively. Because of the close proximity of BP1 and HER2/NEU genes on 17q, correlation between their amplification/expression was also investigated. Increased BP1 copy number was observed in 33% of the cases, with a frequency of 36% and 29% in the PBT and SLN metastasis, respectively. BP1 protein was expressed in 91% of the samples: in all of the PBT with increased BP1 copy number and 65% of PBT with normal copy number. HER2/NEU amplification was detected in 22% of the cases. Concordance between BP1 and HER2/NEU copy numbers was found in 68% of the PBT and 90% of the SLN metastasis. In conclusion, we demonstrated that the BP1 homeobox gene is amplified in breast cancer, both in PBT and SLN metastasis, with a significant correlation with HER2/NEU amplification. Considering that BP1 expression was observed in cases with both increased and normal BP1 copy number, we conclude that other mechanisms in addition to gene amplification play a role in BP1 protein expression.