👉HER-2 expression in breast cancer is primarily assessed semiquantitatively by IHC.
👉The 2013 ASCO / CAP guidelines outline an IHC scoring method based on four classes:
– 0, 1+, 2+, and 3+.
– A score of 0 is negative, indicating no observed staining in invasive tumor cells.
-A score of 1+ is negative and indicates weak, incomplete membrane staining in any proportion of invasive tumor cells or weak, complete membrane staining in less than 10% of invasive tumor cells.
-A score of 2+ is equivocal, indicating circumferential membrane staining that is incomplete and/or weak/moderate and in more than 10% of invasive tumor cells or complete and circumferential membrane staining that is intense and in 10% or less of invasive tumor cells. All 2+ equivocal cases undergo subsequent testing by FISH.
-A score of 3+ is positive and indicates circumferential membrane staining that is complete and intense in a homogeneous and contiguous population, present in more than 10% of invasive tumor cells, and readily appreciated using a low-power objective.
👉FISH is a sensitive and accurate method of scoring invasive breast tumor tissue for HER-2 expression.
👉Initial gene amplification studies by FISH assessment used chromosome 17 centromere (CEP17) or another gene on the same chromosome as an internal control, with a ratio of 2.0 or more considered evidence of HER-2 amplification.
👉These criteria were used as the cutoff for enrollment in trials evaluating HER-2 targeted therapies.
👉In 2007, the ASCO/CAP guidelines were changed to define HER-2 amplified as a ratio of 2.2 or more.
👉More recent guidelines have changed the ratio cutoff back to a ratio of 2.0 or more with the inclusion of criteria to account for HER-2 copy number per tumor cell.
👉Based on the recent guidelines, HER-2 is amplified in cases where the HER-2/CEP17 ratio is 2.0 or more with an average HER-2 copy number of less than 4.0 signals/cell or the HER-2/CEP17 ratio is less than 2.0 with an average HER-2 copy number of 6.0 or more signals/cell using a dual probe or a HER-2 copy number of 6.0 or more copies/cell using a single probe.
👉FISH testing is negative for HER-2 amplification with a HER-2/CEP17 ratio of less than 2.0 with an average HER-2 copy number of less than 4.0 signals/cell or an average HER-2 copy number of less than 4.0 signals/cell using a single probe.
👉Rodrigo Arrangoiz MS, MD, FACS cirujano oncology y cirujano de mamá de Sociedad Quirúrgica S.C en el America British Cowdray Medical Center en la ciudad de Mexico:
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Es experto en el manejo del cáncer de mama.
👉Es miembro de la American Society of Breast Surgeons:
Training:
• General surgery:
• Michigan State University:
• 2004 al 2010
• Surgical Oncology / Head and Neck Surgery / Endocrine Surgery:
• Fox Chase Cancer Center (Filadelfia):
• 2010 al 2012
• Masters in Science (Clinical research for health professionals):
• Drexel University (Filadelfia):
• 2010 al 2012
• Surgical Oncology / Head and Neck Surgery / Endocrine Surgery:
• IFHNOS / Memorial Sloan Kettering Cancer Center:
• 2014 al 2016
Rodrigo Arrangoiz MS, MD, FACS, FSSO 