Comparisons between the typical phenotypes for erbB (neu) (a), myc (b), ras (c), and ret-1 (d).

The erbB-type tumor is a solid, nodular tumor type with slightly atypical nuclei that are intermediate in size between the large myc-type cells (b) and the smaller ras-type cells (c).

The myc-type tumors have large pleomorphic nuclei with a course dark chromatin and dark, amphophilic cytoplasm. These tumors are very aggressive with invasive growth patterns. This tumor is a glandular adenocarcinoma, high grade.

The ras-type tumors have small, uniform nuclei without signi®cant pleomorphism with relatively abundant cytoplasm. The ras-type tumors tend to organize around blood vessels to form papillary type growth patterns. This tumor would be classified as a papillary carcinoma, low grade.

The ret-1-type tumor forms distinctive glands that are lined by large cells with very pleomorphic nuclei and relatively little cytoplasm and would be classified as a glandular adenocarcinoma, high grade. The scale bar indicates 100 microns