PMP infiltration in solid tumors in human patients. (A) Tissue microarray slides containing 5-μm sections from the indicated human tumors and uninvolved adjacent tissue (“Normal”) were stained with the indicated antibodies and 4′,6-diamidino-2-phenylindole (DAPI). Colon, grade I-II colon carcinoma; lung, grade II lung squamous cell carcinoma; prostate, grade II prostate adenocarcinoma; liver, grade II-III hepatocellular carcinoma; breast, grade II-III invasive ductal carcinoma. α_IIb integrin, green; VWF, red; DAPI, blue. Bottom row, center area insets, original magnification ×3. Bars, 50 μm (n = 4). (B) Representative images from panel A, showing counterstain with fluorescein isothiocyanate (FITC)-Annexin V (AXV; shown as red). α_IIb integrin, green; DAPI, blue. Merged images with DAPI shown to the right; α_IIb integrin/Annexin V overlap appears as yellow. VWF staining was omitted from the merged images for clarity. (C) A section of human lung adenocarcinoma, grade II was incubated with 10³ freshly isolated murine platelets for 15 minutes before being fixed and stained as indicated. Yellow arrowheads indicate ectopic intact platelets. (D) Representative images from human lung cancer array with paired uninvolved tissue, stained as in panel A. (E) Representative images from human colon cancer array with paired uninvolved tissue. Note that some α_IIb integrin-positive platelets can be seen within VWF-labeled blood vessels. (F) Representative image of colon adenocarcinoma, grade III, including adjacent normal tissue, showing PMP infiltration in the uninvolved tissue adjacent to the tumor border (indicated with a dotted line). Bars (B-F), 25 μm. (G) Percentage of PMP⁺ tissues from total assayed tissues for colon adenocarcinomas and lung cancers, and adjacent uninvolved tissue, shown ± standard error of the mean (SEM) (n = 3). Colon, P < .01; lung, P < .004. AC, adenocarcinoma; BAC, bronchioalveolar carcinoma; PC, papillary carcinoma; SCC, squamous cell carcinoma; SCLC, small cell lung cancer.