['A disintegrin and metalloprotease 12 (ADAM12) has multiple domains and functions, and it plays important roles in the development of cancer. We conducted a retrospective study to determine whether the expression of the membrane type of ADAM12 (ADAM12-L) could be a prognostic factor in resected pathological (p-) stage I lung adenocarcinoma.', 'ADAM12-L mRNA expression was quantified by a reverse-transcription polymerase chain reaction in tissue samples from 84 completely resected p-stage I lung adenocarcinoma patients. The patients were divided into ADAM12-L-Low and ADAM12-L-High groups, and correlations with clinicopathologic features were obtained.', 'Five-year survival rates of the ADAM12-L-Low and ADAM12-L-High groups were 95.1% and 71.9%, respectively. The postoperative prognosis for the ADAM12-L-High group was significantly poorer than for the ADAM12-L-Low group (P = 0.006). Multivariate analysis confirmed that high expression of ADAM12-L was an independent factor for poor prognosis (P = 0.007, hazard ratio 8.288). The ADAM12-L-High group was less differentiated and had a significantly higher rate of cancer recurrence.'] Is a disintegrin and metalloprotease 12 ( ADAM12 ) a prognostic factor in resected pathological stage I lung adenocarcinoma?