The prognostic role of DCIS-associated TILs within DCIS subtypes (i.e., HER2+ DCIS with large numbers of TILs versus HER2+ DCIS with small numbers of TILs) is not well known, since the majority of recent studies did not correct for DCIS subtype. The gene discussed is ERBB2; the disease is ductal breast carcinoma in situ.