Relevance of systems biological approach in the differential diagnosis of invasive lobular carcinoma & invasive ductal carcinoma

Breast cancer is a malignant neoplasm originating from breast tissue, most commonly from the inner lining of milk ducts or the lobules that supply the ducts with milk. ILCs and IDCs vary from each other with respect to various histological, biological and clinical features. Remarkably, ductal tumors tending to form glandular structures, whereas lobular tumors are less cohesive and tends to invade in single file. The high degree of similarity in the prognoses of IDC and ILC makes it beneficial to develop a differential diagnostic protocol to classify the two conditions. The main goal of the study is to construct the genetic regulatory network from the microarray data using biological knowledge and constraint-based inferences, in order to explore the potential significant gene regulatory networks that can differentiate IDC and ILC and thereby understand the complex interactions that are influenced by the genetic networks. Out of the 54676 genes present on the GPL570 platform- 29 genes exhibited 4 fold up regulation in case of IDC and 22 in the case of ILC. The ductal and lobular tumors displayed a striking difference in the expression of genes associated with cell adhesion, protein folding, and protein phosphorylation and invasion. Construction of separate gene regulation networks for IDC and ILC on the basis of gene expression altercation can be utilized in understanding the distinction in the possible mechanism that underlies the pathological differences between the two, which can be exploited in identifying diagnostic or therapeutic targets. ABBREVIATIONS: ILC - Invasive lobular c carcinoma, IDC - invasive ductal carcinoma, ER - Estrogen Receptor.