More interestingly, in addition to these two genes, a set of genes related to immune function, such as CXCL13, IGHM, IGLL3P, IGJ and IGKC, were observed to be significantly up-regulated in young breast cancer and CXCL13 showed the most significant difference, implying that abnormality of immune functions may be a potential risk factor for young breast cancer. Here, IGKC is linked to breast cancer.