Numerical aberrations of chromosome 17 and her2/neu gene amplification, her2/neu and p 53 protein expression in breast cancer.

Han, Ki Taek; Oh, Young Hwan; Lim, Poong

Original Article

Journal of the Korean Society of Plastic and Reconstructive Surgeons 1998;25(8):1416-1425.
Published online December 1, 1998.

Numerical aberrations of chromosome 17 and her2/neu gene amplification, her2/neu and p 53 protein expression in breast cancer.

Ki Taek Han, Young Hwan Oh, Poong Lim

Abstract

Breast cancer is one of the leading causes of death attributable to cancer in women. In view of the limitations of conventional predictable factors of the breast cancer, additional second-generation parameters would be valuable in selecting the patients who would be most likely to be beneficial from adjuvant therapy and breast reconstruction. The author investigated the HER2/neu gene amplification and the number of chromosome 17 in 39 cases of paraffin embedded breast cancer tissues, 20 cases without lymph node metastasis and 19 cases with lymph node metastasis, using fluorescent in situ hybridization(FISH) and compared the results with HER2/neu and p 53 protein expression detected by immunohistochemical method. Eleven cases fibroadenoma were used as benign tumor control. Numerical aberrations of chromosome 17 were found in 17 out 39 breast cancer cases (44%)(monosomy in 10 cases, 26%; trisomy in 3 cases, 8%; tetrasomy in 3 cases, 8%; polysomy in 1 case ,3%), and the frequency of each type aberration was not significantly different between the negative and positive groups in lymph node metastasis. Monosomy of chromosome 17 was found in 2 out of 11(12%) fibroadenoma cases. HER2/neu gene amplification was found in 8 out of 39 cases (19%) and other 2 cases revealed HER2/neu gene amplification in lymph node metastatic tumor only, not in original tumor. Fourteen out of 19 cases of breast cancer with lymph metastasis showed HER2/neu protein expression both in original and metastatic tumors. All of the six cases showing HER2/neu gene amplification in original and/or metastatic tumor revealed HER2/neu protein expression. The frequency of HER2/neu gene amplification in the 39 breast cancer cases was not different between metastatic and non-metastatic groups(p= 0.284). However, HER2/neu protein expression was increased significantly in the metastatic group(p=0.028). None of the 11 fibroadenoma cases revealed HER2/neu gene amplification or HER2/ neu protein expression. Nine out of 19 cases of breast cancer with lymph node metastasis showed p 53 protein accumulation in original tumor(47%), but 3 of them revealed p 53 protein accumulation only in original tumor. The frequency of p 53 protein accumulation was not significantly different between metastatic and non-metastatic groups. None of the 11 fibroadenoma cases revealed p 53 protein accumulation. In conclusion, there are no differences between the lymph node metastatic group and non-metastatic groups in numerical aberrations of the chromosome 17 , amplification of the HER2/neu gene expression and accumulation of the p 53 protein in breast cancer. However, the HER2/neu protein expression was increased significantly in lymph node metastatic group, so it could be one of the predictors of the metastasis in breast cancer.