Clinicopathologic and immunohistochemical analyses in lung metastasis of colorectal carcinoma

We compared the immunohistochemical staining patterns of carcinoembryogenic antigen (CEA), CA19-9 and proliferating cell nuclear antigen (PCNA) between specimens from 13 patients who had undergone surgery for colorectal carcinoma with lung metastasis (lung metastasis group) and specimens from 13 patients who had no evidence of recurrence or metastasis within at least 5 years after colorectal resection (no metastasis group). The PCNA labeling indices of primary and metastatic lesions were 53.29 8.88% and 63. 26 6.21% (p<0.001), respectively. The PCNA labeling index in the no metastasis group was 26 12.9% (p<0.001). There was no significant difference in the CA19-9 staining patterns between the two groups. The CEA distribution patterns in the primary and lung metastatic lesions were different even in the same case. The original tumor cells showed apical or C1 localization, whereas metastatic cells showed C2 localization. These findings indicate that patients having colorectal carcinoma with a high PCNA labeling index have a high probability of lung metastasis, and that the CEA distribution pattern would change after original tumor resection.