Molecular diagnosis of MACC1 status in lung adenocarcinoma by immunohistochemical analysis.

Recently, we reported that overexpression of metastasis-associated colon cancer-1 (MACC1) mRNA may be a useful marker for predicting postoperative recurrence in patients with lung adenocarcinoma following surgery. However, the biological significance of mRNA overexpression is difficult to determine and is not widely used because mRNA expression analysis is relatively expensive and time- and labor-intensive. On the other hand, immunohistochemical (IHC) staining is easy to perform, well-established, inexpensive, and is a useful method which can be routinely applied in solid tumor diagnosis in clinical laboratories.Tumor specimens were collected from 197 consecutive patients who underwent a complete resection for lung adenocarcinoma from 1998 to 2007. We analyzed the MACC1 status of the primary lung adenocarcinoma by IHC analysis.The average postoperative observation period was 46.7 months. Forty (20.3%) of the 197 patients developed recurrences after surgery. Positive expression of MACC1 was identified in 129 (65.5%) patients. Furthermore, MACC1 IHC was positive in 33 (82.5%) out of the 40 patients and 96 (61.1%) out of the 157 patients, with and without recurrence, respectively (p=0.011). Both univariate and multivariate logistic regression models indicated that positive staining for MACC1 was an independent factor for tumor recurrence. Furthermore, positive staining for MACC1 was associated with poorer disease-free survival (DFS), according to the univariate survival analysis (p=0.080).Positive staining for MACC1 expression in resected specimens was associated with a poorer DFS. Therefore, positive staining of IHC for MACC1 may be a useful marker for predicting postoperative recurrence in patients with lung adenocarcinoma following surgery.