Differential immune cell densities in ductal carcinoma In-Situ and invasive breast cancer: Possible role of leukocytes in early stages of carcinogenesis

Objectives: To investigate immune cell densities in pre-neoplastic (DCIS), cancer (IDC) and control breast tissues. Methods: A total of four preneoplastic, 104 cancer and 104 control samples were analyzed. Morphological classification and prognostic scoring along with quantification of immune cells/mm2 was performed. Data were entered and analyzed using SPSS version 16. Correlation of immune cell densities with various tumour sub-types was investigated using paired t-test and ANOVA. A p-value of 0.05 was considered as significant. Results: Our data show increased infiltration of lymphocytes (mean lymphocytes = 287.6cells/mm2) as well as myelocytes (mean lymphocytes = 117.1cells/mm2) in pre-neoplastic tissues. This infiltration was significantly high compared to cancer (p-value 0.001) as well as control tissues (p-value 0.001). Moreover, we report increased infiltration of lymphocytes in cancer tissues compared to controls (p-value 0.001). There was no difference in lymphocyte densities within various tumour sub-types (all p-values 0.05). Conclusion: Leukocytes may play a role in early stages of breast carcinogenesis.