Effect of the expression of Y477F ezrin on local invasion of AC2M2 breast carcinoma cells: Two clones of AC2M2 cells expressing Y477F ezrin (A43 and C13) or empty pCB6 vector were engrafted into the mammary fat pad of nude mice. Primary tumors from the mice were excised after 21 or 23 days, and photographs of gross pathology (Panels A, D) were taken. Scale bar = 0.5 cm. 5 μm sections of FFPE processed tissues were stained with hematoxylin and eosin for histopathological analysis. Arrows indicate invasion of pCB6 tumor into underlying abdominal muscle wall (Panels A, B) or draining lymph node (Panel C). In contrast, Y477F ezrin tumors showed no adhesion to abdominal wall (Panels D, E) and rarely penetrated into the circumscribed tumor margin (Panel E) or adjacent lymph node (Panel F). Invasion was assessed categorically (presence or absence), based on combined observations of gross and histopathology. Data were expressed as the proportion of mice with local invasion relative to the total number of mice per group. Significant difference between pCB6 control and Y477F ezrin-expressing clones (A43 and C13) in two pooled experiments is shown (p = 0.003, two-sided Fisher Exact test). The overall p value for A43 + C13 clones combined is 0.0002 (Panel G). Label with "T" indicates tumor, "Mus" indicates muscle and "LN" indicates lymph node. Image magnification is shown in each panel.