HER-2 protein overexpressing breast cancer without gene amplification shows higher hormone receptor expression than HER-2 protein overexpressing breast cancer with gene amplification.
Cases of breast cancer showing human epidermal growth factor receptor-2 (HER-2) protein overexpression without corresponding gene amplification have been found in immunohistochemistry (IHC) and fluorescent in situ hybridization (FISH) results. We investigated the clinicopathological characteristics of cases showing HER-2 protein overexpression breast cancer without gene amplification (IHC3+/FISH-) and compared them to cases showing HER-2 protein overexpression breast cancer with gene amplification (IHC3+/FISH+). This study was conducted on 90 patients with HER-2 IHC3+ breast cancer. The clinicopathological factors analyzed included tumor size, histological grade, nuclear grade, nodal involvement, and hormone receptor status. HER-2 IHC3+/FISH- breast cancer was found in 14 of 84 tumors (16.7%) and showed a statistically significant lower histological and nuclear grade (P = .000) and higher expression of estrogen receptors (ERs) and progesterone receptors (PRs) (P = .006) than IHC3+/FISH+ breast cancer. In conclusion, HER-2 IHC3+/FISH- breast cancer could be a subgroup showing lower histological/nuclear grade and higher expression of ERs/PRs.
Koo
Ja Seung
JS
Department of Pathology, Yonsei University Health System, Seoul, South Korea.
Jung
Woohee
W
Yang
Woo Ick
WI
D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000235:genetics* / Q000378:metabolism / Q000556:secondary; D002869:Chromosome Aberrations; D005260:Female; D005784:Gene Amplification; D020869:Gene Expression Profiling; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D060787:Neoplasm Grading; D009367:Neoplasm Staging; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*
D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human