The background and upper-left images are Steiner stains of gastric antral biopsies from an H. pylori-positive patient (upper left) and an H. pylori-negative patient (background; photomicrographs courtesy of Zhiheng Pei, M.D., Ph.D., New York Harbor Department of Veterans Affairs Medical Center and New York University Langone Medical Center). H-pylori-positivity is associated with risk of gastric cancer, whereas H. pylori-negativity is associated with risk of esophageal adenocarcinoma. The presence of H. pylori (upper left) is indicated by the dark curved bacilli in the mucus layer adjacent to the epithelial cell surfaces. The H. pylori-positive biopsy shows deeper staining of the epithelial cells, indicating tissue reactivity, and the lamina propria shows increased mononuclear cell numbers (compared with the H. pylori-negative biopsy). The biopsies were formalin-fixed and paraffin-embedded. See articles by Blaser (beginning on page 308) and by Islami and Kamangar (beginning on page 329) for more information. The larger, composite image contains representative microphotographs (40× magnification) of a lung adenocarcinoma (main image; HE staining) and of immunohistochemical expression of the markers phosphorylated (p)-CREB (top inset), CXCL5 (bottom inset), and NF- κB (upper-middle inset) in malignant lung epithelial cells and CXCR2 (lower-middle inset) in malignant lung epithelial cells and in endothelial cells within the microenvironment. See articles by Strieter (beginning on page 305) and by Sun et al. (beginning on page 316) for more information.

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