Cancer Diagnosis Program | Biorepositories and Biospecimen Research Branch

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An approach to interpreting immunohistochemical stains of adenocarcinoma in small needle core biopsy specimens: the impact of limited specimen size.

Author(s): Goldstein NS, Bosler D

Publication: Am J Clin Pathol, 2007, Vol. 127, Page 273-81

PubMed ID: 17210515 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   This study examined the effects of needle gauge on interpreting IHC staining of colorectal adenocarcinoma hepatic metastases specimens. A single tissue block from twenty cases of metastatic colorectal adenocarcinoma hepatic resections was used to create an H&E-stained slide for digital imaging and five 3-µm-thick consecutive sections were IHC stained for CK AE1/AE3, CK7, and CK20.  The proportion of CK7- and CK20-immunoreactive cells was determined by comparison to the CK AE1/AE3-stained cells. Twenty cases of hepatic metastases of adenocarcinoma collected by radiologically-guided needle core biopsies with either an 18-gauge(G) or 20-G biopsy needle (10 each) were used to create rectangular templates based on the mean values of the needle core dimensions from all the cases. Needle core templates were superimposed over digital images of the CK7- and CK20-stained slides in 7 different areas of each image (1 from the area with least immunoreactivity, 1 from the area of greatest immunoreactivity, 5 from random regions) and independently evaluated for percentage of immunoreactive cells.

   Summary of Findings:

   Compared to biopsies obtained with 20G needles, those obtained with 18G needles had higher mean needle core length (13.71 versus 9.14 mm), core width (0.47 versus 0.31 mm), and mean area of adenocarcinoma (14.87 versus 6.12 mm²). Mean percentage of CK20+ cells was comparable in low-magnification visualization of the entire IHC slide (72.50%) and in the magnified digital images of the slides (77.10%).  However, when areas corresponding to 18G or 20G cores were evaluated, only 47.0% and 52.13% of cells were CK20+, respectively. Similarly, the mean percentage of CK7+ cells on IHC slides decreased from 28.4% in the specimens as a whole to 16.50% when areas corresponding to 20G biopsies were considered and 19.21% for areas corresponding to 18G biopsies. The percentage of CK20+ cells remained at 100% when 10% immunoreactivity was used as the cut point for a positive result, regardless of area considered. However, all cases were considered CK20+ positive in the biopsy area using a 25% threshold only when the mean value of the overall case (7 images) or the 3 images with the highest percentage of immunoreactive adenocarcinoma cells were used and all cases were CK20+ using a 50% threshold only when the mean of the 3 images with the highest percentage of cells were considered. Similarly, CK7+ results for biopsy areas were most comparable to the resection specimen at the 50% cut-off when the 3 most stained specimens were considered. The percentage of cells that were CK7–/CK20+ (the immunophenotype which is associated with most colorectal adenocarcinomas) increased with increasing threshold for positivity in the entire specimen (25%, 50%, and 85% at 10%, 25%, and 50% staining cut points, respectively). The number of needle core template cases that were CK7–/CK20+ also increased with the higher cut points with the greatest correlation to resection specimens observed when using the mean staining of the 3 images with the highest percentages of immunoreactive cells (20%, 30%, and 95% of 18G and 15%, 25% and 80% of 20G cases using 10%, 25%, and 50% staining as the cut point, respectively).

   Biospecimens

   • Tissue - Liver

   Preservative Types

   • Formalin

   Diagnoses:

   • Neoplastic - Carcinoma

   Platform:

   Analyte	Technology Platform
   Protein	Immunohistochemistry

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Immunohistochemistry Specific	Targeted peptide/protein	CK AE1/AE3 CK7 CK20
   Biospecimen Acquisition	Needle gauge	20-gauge 18-gauge

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