Abstract
Breast cancer is the most common cancer among the population as a whole and among females, yet it is highly curable if diagnosed at an early stage. Different methods are used to diagnose breast cancer. One of these methods features immunological tests using flow cytometry to determine T-lymphocyte (CD4/CD8) ratios in peripheral blood. One hundred patients with breast cancer (50 from Basra, Iraq, and 50 from Baku, Azerbaijan) confirmed to have breast cancer by histopathology were studied. Blood samples were collected from all patients before initiation of treatment and were used for analysis. The mean age of women from Basra was $51.2{\pm}10.7years$ and that of women from Baku was slightly higher at $54.8{\pm}12.2$. The mean CD4/CD8 ratio in Basra was 1.4 and in Baku was 1.8 with P value < 0.05. The percentage of Basra patients who have CD4/CD8 value less than 1 was 50%, while the percentage for Baku patients was 24 % (p < 0.05). While the CD4/CD8 T-lymphocyte ratio might be useful for early diagnosis in patients with breast cancer parallel with other confirmed tests factors involved in explaining variation between countries such as that observed here need to be taken into account.