Mucin 1 expression correlation with lymph node metastasis and micrometastasis and poor prognosis in patients with esophageal squamous cell carcinomas

Introduction: Lymph node metastasis (LNM) and lymph node micrometastasis (LNMM) are prognostic factors in esophageal squamous cell carcinoma (ESCC) patients. The purpose of this research is to investigate whether mucin 1 expression detected by immunohistochemistry in lymph nodes correlates with LNM, LNMM and prognosis in ESCC patients.Material and methods: There were 92 ESCC patients enrolled in the research, and 1382 lymph nodes were obtained from these 92 patients. All lymph nodes were immunohistochemically analyzed using an anticytokeratin and mucin 1 antibody cocktail.Results: In the pN1-2 patients' group, 68 lymph nodes from 15 patients had tumor metastasis. All these 68 tumor metastatic lymph nodes were positive for mucin 1. Mucin 1 was detected in another 231 lymph nodes and among them, 3 (3/231 1.3%) lymph nodes from 2 (2/15 13.3%) patients were positive for mucin 1. In 77 pN0 patients, mucin 1 was detected in 1083 lymph nodes from the 77 patients; 17 (17/1083 1.6%) lymph nodes from 15 (15/77 19.5%) patients were positive for mucin 1. The 5-year survival rate was 39.1%, and it was significantly related to tumor invasion (pT, p < 0.05), lymph node metastasis (pN, p < 0.01), pTNM stage (p < 0.01) and mucin 1 expression (p < 0.01). Cox regression of multivariate analysis demonstrated that mucin 1 expression and pT were independent prognostic factors.Conclusions: Mucin 1 expression was related to LNM and LNMM and poor prognosis in ESCC patients. Immunohistochemistry for mucin 1 can be applied for the detection of LNM and LNMM.