Scoring

Protein Immunohistochemistry (IHC)

Stained IHC specimens are scored with a microscope by pathologists with the H-score, a semi-quantitative score system which calculates a score from 0 to 300 based on both the intensity of tumor cytoplasmic staining and the percentage of cells stained. Intensity is considered "0" for absent expression, "1+" for weak staining, "2+" for moderate staining, and "3+ for strong staining. The H-score is calculated as follows: H-Score = (0 x percentage of cells with absent cytoplasmic staining) + (1 x percentage of "1+" cells) + (2 x precentage of "2+" cells) + (3 x percentage of "3+ cells)

RNA in-situ hybridization (ISH)

Specimens stained with RNA ISH are scored with a microscope by pathalogists using an adapted version of the suggested RNA Scope scoring system with a semi-quantitative score ranging from 0 to 4 based ont he amount of RNA signal (dots to clusters) visualized in the cells. A score of "0" represents no signal. "1" for 1-3 dots per cell. "2" for 4-10 dots per cell, "3" for >10 dots per cell and less than 10% of cells with clusters, and "4" for >10 dots per cell or more than 10% of cells with clusters.

DNA silver in-situ hybridization (SISH)

Specimens stained with DNA SISH are scored with a microscope by pathologists using an adapted version of the 2013 College of American Pathologist (CAP) guidelines for ERBB2 (HER2) SISH scoring. Gene (black) and centromere (pink) signals are counted in at least 20 tumor cells and the average gene signal and ratio of gene-to-centromere signal per cell are calculated. Standard criteria for amplification positivity are gene signal greater than or equal to four or gene-to-centromere ratio greater or equal to two; however, allowance is made for different specific criteria for positivity based on biomarker characteristics and literature research.