Breast cancer still remains as the most frequent cancer with second mortality rate in women worldwide. Thereare no validated biomarkers for detection of the disease in early stages with effective power in diagnosis andtherapeutic approaches. Cancer/testis antigens are recently promising tumor antigens and suitable candidatesfor targeted therapies and generating cancer vaccines. We conducted the present study to analyze transcriptchanges of two cancer/testis antigens, OIP5 and TAF7L, in breast tumors and cell lines in comparison withnormal breast tissues by quantitative real time RT-PCR for the first time. Significant over-expression of OIP5was observed in breast tumors and three out of six cell lines including MDA-MB-468, T47D and SKBR3. Notsignificant expression of TAF7L was evident in breast tumors but significant increase was noted in three out ofsix cell lines including MDA-MB-231, BT474 and T47D. OIP5 has ssignificant role in chromatin organizationand cell cycle control during cell cycle exit and normal chromosome segregation during mitosis and TAF7L is acomponent of the transcription factor ІІD, which is involved in transcription initiation of most protein codinggenes. TAF7Lis located at X chromosome and belongs to the CT-X gene family of cancer/testis antigens whichcontains about 50% of CT antigens, including those which have been used in cancer immunotherapy.