Investigation of telomerase activity in inflammatory and noninflammatory breast cancer.

Abstract

e21055 Background: Inflammatory breast cancer (IBC) is an aggressive type of breast cancer disease that has a high incidence in Egypt than western countries. It is characterized by rapid progression, involvement of dermal lymphatic emboli and extensive lymph node involvement. Basic and translational studies needed to define IBC disease biology and identify specific biomarkers have been limited by the paucity of patient samples. Hence, the current study aimed to introduce the telomerase activity level as a novel diagnostic marker for breast cancer and specifically for IBC to be differentiated from non-IBC. Methods: Breast cancer patients were enrolled from Ain Shams University hospitals in Cairo, divided into two groups: IBC (n=26) and non-IBC (n=27). Tissue samples were collected during modified radical mastectomy. TRAP (Telomerase repeat amplification protocol) assay was used to assess the telomerase activity in inflammatory and non inflammatory breast cancer tissue samples and their representative cell lines, SUM149 and MCF-7 respectively. Immunohistochemistry was used to investigate the expression of hTERT subunit of telomerase in paraffin embedded tissue samples of both types of patients. MTT assay was used to compare the effect of AZT (3’-azido-3’-deoxythymidine) on the growth of cell lines SUM149 and MCF-7. Results: : IBC showed Telomerase activity ranged from 12 to 376 units with a mean value of 75 and a median value of 43, while telomerase activity in non-IBC ranged from 6 to 109 units with a mean value of 35 and a median value of 24. On the other hand, normal tissues showed telomerase activity below 5 (P > 0.001). Using immunohistochemistry, the hTERT expression was higher in IBC than non-IBC and no expression at all in normal tissues. Also, a positive correlation was found between the telomerase activity and the number of metastatic lymph nodes in both IBC (r =0.511) and non-IBC (r =0.622). Besides, IBC cell line showed a faster response (53%) to telomerase inhibition by AZT after 24 hrs than non-IBC cell line (13%) at the same conditions. Conclusions: Telomerase could be a promising marker at the diagnostic and therapeutic levels in breast cancer and specifically in IBC.