CTLA4 and breast cancer: The present study showed that CTLA4 tumor expression was associated with poor prognostic parameters as there is significant association between low CTLA4 expression in tumor cells and low tumor stage (T1) and absent vascular invasion, also a trend of significance with (N0) nodal stage and these results come in line with Yu et al., (2015) and Wang et al., (2007) who found that the CTLA-4 gene may be associated with the progression of breast cancer in the Chinese Han population.