Fig. 1.

Immunohistochemical analysis of Beclin-1 and HIF-1α in esophageal squamous cell carcinoma. a Positive Beclin-1 immunoreactivity in cytoplasm of normal squamous epithelial cells. b Negative Beclin-1 immunoreactivity in tumour cells. c Positive Beclin-1 immunoreactivity in cytoplasm and cytomembrane of tumour cells. d In normal squamous epithelial cells, HIF-1α immunoreactivity was not detected. e Weak HIF-1α immunoreactivity in cytoplasm of tumour cells. f Strong HIF-1α immunoreactivity in tumour cells. Original magnification: a, e and f, ×200; b and d, ×100; c, ×400