EGFR Gene Amplification and Protein Expression in Invasive Ductal Carcinoma of Breast
Won Hwangbo, Sangjeong Ahn, Jeonghyeon Lee, Seojin Kim, Chulhwan Kim, Insun Kim. Korea University Anam Hospital, Seoul, Korea
Background: The expression of epidermal growth factor receptor (EGFR) is used as marker for basal-like breast cancer, but it has been recently suggested that EGFR can be a target of breast cancer treatment.
Design: Between September 2005 and July 2011, 691 invasive ductal carcinomas of breast were diagnosed and immunophenotyped according to the expression of ER, PR, Her-2, EGFR, c-kit and CK5/6. The expression of EGFR was scored using same criteria as for Her-2 expression. Eighty-two cases (13 1+ expression, 42 2+ expression and 27 3+ expression) were studied for gene expression using FISH technique.
Results: EGFR expression. Results: EGFR expression 2+ and 3+ was found in 76 of 691 cases (11%), and 18 cases co-expressed Her-2, 47 cases with other basal markers, and 11 cases expressed only EGFR. In amplification study, one of 13 EGFR 1+ cases (8%), 5 of 42 EGFR 2+ cases (12%), and 7 of 27 EGFR 3+ cases (26%). The EGFR gene amplification was seen in 5 of 16 (31%) Her-2-co-expression group, 2 of 12 (17%), EGFR only expression group and 6 of 54 (11%) basal-like group.
Conclusions: This study showed EGFR expression was associated with gene amplification in certain proportion of the breast cancers. Further study should be followed to determine the benefit of EGFR-directed therapy as well as to evaluate the clinical outcome of Her-2 and EGFR co-expressing patients.
Wednesday, March 21, 2012 1:00 PM
Poster Session VI # 28, Wednesday Afternoon