Gastric/Gastroesophageal (GE) Junction HER2/Neu Immunohistochemistry with Reflex to FISH » Pathology Laboratories » College of Medicine

Additional Information:

HER2 Interpretation	Staining Intensity Score	Surgical Resections	Biopsies
Negative	0	No reactivity or membranous reactivity in < 10% of tumor cells	No reactivity or membranous reactivity in < 5 clustered tumor cells
Negative* (*reflex FISH)	1+ (40x)	Faint/barely perceptible membranous reactivity in > 10% of tumor cells; cells are reactive only in part of their membrane	Tumor cell cluster (> 5 cells) with a faint/barely perceptible membranous reactivity irrespective of percentage of tumor cells stained.
Equivocal* (*reflex FISH)	2+ (10 – 20x)	Weak-to-moderate complete, basolateral or lateral membranous reactivity in > 10% of tumor cells	Tumor cell clusters (> 5 cells) with a weak to moderate complete, basolateral or lateral membranous reactivity irrespective or percentage of tumor cells stained.
Positive	3+ (2.5 – 5x)	Strong complete, basolateral or lateral membranous reactivity in > 10% of tumor cells	Tumor cell clusters (> 5 cells) with a strong complete, basolateral or lateral membranous reactivity irrespective of percentage of tumor cells stained.
^References: ^{Hofmann M, Stoss O, Shi D, Buttner R, van de Vijver M, Kim W, et al. Assessment of a HER2 scoring system for gastric cancer: results from a validation study. Histopath 2008; 52:797-805.} ^{Ruschoff J. HER2 diagnostics in gastric cancer-guideline validation and development of standardized immunohistochemical testing. Virch Arch 2010; 457:299}

CPT Code(s):

88360 FISH reflex
88368 x 2

Specimen Requirements:

A paraffin block containing the representative gastric/GE junction tumor or at least 5 unstained slides

Unacceptable Conditions: Frozen

Stability: Indefinite

Use:

This test is used to determine eligibility for anti-HER2/Neu therapies in gastric and gastroesophageal (GE) junction tumors.

Methodology:

Immunohistochemistry

Reported:

Immunohistochemistry is reported within 7 days. If Gastric HER2/Neu FISH is requested, the report will be provided within 9 days.

Reference Values:

In Notes below

Interpretation Data:

Surgical Specimens (Resections): A score of 0 is no reactivity or membranous reactivity (staining) in or = 10% of invasive tumor cells.

Biopsy Specimens: A score of 0 is no reactivity or no membranous reactivity (staining) in less than 5 clustered tumor cells. A score of 1+ is tumor cell clusters (greater than or equal to 5 cells) with a faint/barely perceptible membranous reactivity (staining) regardless of percentage of invasive tumor cells stained. A score of 2+ is tumor cell clusters (greater than or equal to 5 cells) with a weak-to-moderate complete, basolateral or lateral membranous reactivity (staining) regardless of percentage of invasive tumor cells stained. A score of 3+ is tumor cell clusters (greater than or equal to 5 cells) with a strong complete, basolateral or lateral membranous reactivity (staining) regardless of percentage of invasive tumor cells stained.