Figure 1.
RCAS-ErbB2 induces solid, poorly differentiated tumors with spindloid metaplasia. (A) Based on hematoxylin and eosin staining, histopathological comparison between mammary tumors arising from Krt6a-tva mice infected with RCAS-PyMT (107 IU, 5 weeks; n= 8) and RCAS-ErbB2 (107 IU, 5 weeks; n = 8). (B) Keratin 6 was measured via immunohistochemical staining of tumors induced by PyMT (n = 7) and ErbB2 (n = 8), with (C) quantitation of Krt6a-positivity, defined by presence of Krt6a-positive cells in the majority (≥3) of 5 random fields. (D) Pancytokeratin was measured via immunohistochemical staining of tumors induced by PyMT (n = 7) and ErbB2 (n = 6), with (E) quantitation of the mean percentage of pancytokeratin+ cells in PyMT and ErbB2 induced tumors. (F) Keratins 5 and 8 were measured by immunofluorescence staining of tumors induced by PyMT (n = 7) and ErbB2 (n=10), with (G) quantitation of the mean percentage of Krt5+ cells in PyMT and ErbB2 induced tumors.