In accordance with these findings, the benign character of the AA in our patient was evident on the basis of the immunohistochemical studies showing an absence of Ki-67 and p63 staining that was in contrast to the malignant character of the primary carcinoma of the lung diagnosed on the basis of a high Ki-67 proliferation index and a focally positive p63 status. The gene discussed is MKI67; the disease is lung carcinoma.