Fig. 1

Lobular carcinoma in situ in association with invasive lobular carcinoma. Histological sections from multiple patients capture areas of lobular carcinoma in situ (LCIS) that appear to have focal myoepithelial layer disruption adjacent to invasive lobular carcinoma (ILC), suggesting possible progression of LCIS to ILC at such transitions. Green hatched lines mark the myoepithelial layer; orange arrows are possible foci of myoepithelial disruption; yellow arrows highlight invasive cells. In addition to the cells marked by yellow arrows, additional ILC cells are present in each image throughout the stroma, surrounding the areas of LCIS