The prognostic value of keratin pearls in patients with esophageal squamous cell carcinoma.

Keratin pearls (KP) is an important indicator of the degree of tumor cell differentiation of esophageal squamous cell carcinomas (ESCC). However, the independent prognostic value of KP in ESCC patients remains unclear. The hematoxylin-eosin (H&E) stained tissue microarrays (TMAs) or whole slides of the patients were prepared to identify the existence of KP. Kaplan-Meier (KM) survival analysis as well as univariate and multivariate Cox regression analyses were used to evaluate the prognostic value of KP. A nomogram based on KP and other clinicopathologic characteristics was constructed. The C-index, calibration curve, Receiver Operating Characteristic (ROC) curve, and Decision Curve Analysis (DCA) were used to evaluate the nomogram. The results indicated KP is a protective factor against lymph node metastasis and is closely associated with the differentiation degree in ESCC patients. KM survival analysis showed that the overall survival (OS) of patients with KP was significantly better than for patients without KP. In addition, multivariate Cox regression analysis revealed that KP was an independent predictor of OS. Furthermore, ROC curve demonstrated that KP combined with differentiation degree could more accurately predict the 5-year survival rate than differentiation degree alone. Importantly, the nomogram showed good discrimination and calibration abilities in both training and validation groups, which could more accurately predict the 3-, 5-, and 10-year survival rates of ESCC patients and adds to the predictive value of TNM stage alone. In conclusion, KP is an independent predictor of prognosis in patients with ESCC and provides incremental prognostic value to degree of differentiation.