ILC is, compared to IDC, more often associated with higher age at diagnosis, larger tumour size, multicentricity, multifocality, bilaterality, histological grade 2, hormone receptor positivity, HER2 negativity, different metastatic pattern, lower cell proliferation rate and less responsiveness to chemotherapy (Arpino et al. 2004; Pestalozzi et al. 2008; Rakha et al. 2008a; Wiesner et al. 2009; Petrelli & Barni 2013). The gene discussed is ERBB2; the disease is neoplasm.