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

To investigate immune cell densities in pre-neoplastic [DCIS], cancer [IDC] and control breast tissues. A total of four preneoplastic, 104 cancer and 104 control samples were analyzed. Morphological classification and prognostic scoring along with quantification of immune cells/mm[2] 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. Our data show increased infiltration of lymphocytes [mean lymphocytes = 287.6 cells/mm[2]] as well as myelocytes [mean lymphocytes = 117.1 cells/mm[2]] 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]. Leukocytes may play a role in early stages of breast carcinogenesis