Squamous cell carcinoma (SCC) of the external auditory canal (EAC) is rare, usually presents at an advanced stage, and is a more aggressive
tumor with poor prognosis. The University of Pittsburgh TNM staging system commonly used in prognostication is not perfect, and more accurate
biomarkers predicting prognosis are needed.
Tumor budding is an established negative prognostic factor at the invasive front in
colorectal cancer. Moreover, immunohistochemical studies showed that
laminin 5-γ2 (Ln5-γ2) is expressed at the invasive front in
tumor or
tumor budding cells. We assessed the prognostic significance of
tumor budding and Ln5-γ2 expression by performing Ln5-γ2 immunohistochemistry and evaluated the degree of
tumor budding in pre-treatment biopsy specimens, and investigated their correlations to clinicopathological parameters in patients with SCC of the EAC. Patients whose
tumors had high budding grade and Ln5-γ2 expression had significantly shorter survival times. Budding grade was significantly correlated with Ln5-γ2 expression. Multivariate analysis revealed that high budding grade predicted poorer prognosis regardless of disease stage. Our results suggested that budding grade and Ln5-γ2 expression can be used as indicators of poor prognosis in patients with SCC of the EAC.