Challenges posed to pathologists in the detection of KRAS mutations in colorectal cancers

Jonathan Dudley, Li Hui Tseng, Lisa Rooper, Marco Harris, Lisa Haley, Guoli Chen, Christopher Gocke, James Eshleman, Ming-Tseh Lin

Research output: Contribution to journalArticle

Abstract

Context.-Detection of KRAS mutation is mandatory to predict response to anti-epidermal growth factor receptor monoclonal antibodies in patients with metastatic colorectal cancers. Objective.-To demonstrate challenges posed to pathologists in the clinical detection of KRAS mutations in colorectal cancers. Design.-In this retrospective analysis for quality assessment of the pyrosequencing assay, we survey the characteristics of 463 formalin-fixed, paraffin-embedded neoplastic tissues submitted for KRAS mutation detection during a 26-month period. Results.-The KRAS mutation was detected in 39.2% of tumors. This included 2 tumors with complex pyrograms (GGT>GAG at codon 12 and GGC>GTT at codon 13, as resolved by a Pyromaker software program) and 3 tumors with an indeterminate percentage of mutant alleles (defined as 4% to 5% and confirmed by a next-generation sequencing platform). Among the 25 specimens (5.5%) with fewer than 20% tumor cells, 22 were resected after chemotherapy/radiation. Significant depletion of tumor cells was observed in rectal cancers resected after neoadjuvant therapy (31.0%) versus those without previous treatment (0%) (P = .01). We also explore other specimens with low tumor cellularity and potential causes of discrepancy between the estimated tumor cell percentage and detected mutant allele frequency, such as intratumor heterogeneity of KRAS mutation. Conclusions.-Neoadjuvant therapy may deplete tumor cells and confound the molecular diagnosis of KRAS mutations. Accurate detection of specimens with poor tumor cellularity requires the appropriate selection of neoplastic tissues, evaluation of tumor cellularity, use of assays with high sensitivity, and prospective quality assessment.

Original languageEnglish (US)
Pages (from-to)211-218
Number of pages8
JournalArchives of Pathology and Laboratory Medicine
Volume139
Issue number2
DOIs
StatePublished - Feb 1 2015

Fingerprint

Colorectal Neoplasms
Mutation
Neoplasms
Neoadjuvant Therapy
Codon
Pathologists
Rectal Neoplasms
Epidermal Growth Factor Receptor
Gene Frequency
Paraffin
Formaldehyde
Software
Alleles
Monoclonal Antibodies
Radiation
Drug Therapy

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Medical Laboratory Technology
  • Medicine(all)

Cite this

Challenges posed to pathologists in the detection of KRAS mutations in colorectal cancers. / Dudley, Jonathan; Tseng, Li Hui; Rooper, Lisa; Harris, Marco; Haley, Lisa; Chen, Guoli; Gocke, Christopher; Eshleman, James; Lin, Ming-Tseh.

In: Archives of Pathology and Laboratory Medicine, Vol. 139, No. 2, 01.02.2015, p. 211-218.

Research output: Contribution to journalArticle

@article{4c0b6906ba124cfb9f748ef61e27f188,
title = "Challenges posed to pathologists in the detection of KRAS mutations in colorectal cancers",
abstract = "Context.-Detection of KRAS mutation is mandatory to predict response to anti-epidermal growth factor receptor monoclonal antibodies in patients with metastatic colorectal cancers. Objective.-To demonstrate challenges posed to pathologists in the clinical detection of KRAS mutations in colorectal cancers. Design.-In this retrospective analysis for quality assessment of the pyrosequencing assay, we survey the characteristics of 463 formalin-fixed, paraffin-embedded neoplastic tissues submitted for KRAS mutation detection during a 26-month period. Results.-The KRAS mutation was detected in 39.2{\%} of tumors. This included 2 tumors with complex pyrograms (GGT>GAG at codon 12 and GGC>GTT at codon 13, as resolved by a Pyromaker software program) and 3 tumors with an indeterminate percentage of mutant alleles (defined as 4{\%} to 5{\%} and confirmed by a next-generation sequencing platform). Among the 25 specimens (5.5{\%}) with fewer than 20{\%} tumor cells, 22 were resected after chemotherapy/radiation. Significant depletion of tumor cells was observed in rectal cancers resected after neoadjuvant therapy (31.0{\%}) versus those without previous treatment (0{\%}) (P = .01). We also explore other specimens with low tumor cellularity and potential causes of discrepancy between the estimated tumor cell percentage and detected mutant allele frequency, such as intratumor heterogeneity of KRAS mutation. Conclusions.-Neoadjuvant therapy may deplete tumor cells and confound the molecular diagnosis of KRAS mutations. Accurate detection of specimens with poor tumor cellularity requires the appropriate selection of neoplastic tissues, evaluation of tumor cellularity, use of assays with high sensitivity, and prospective quality assessment.",
author = "Jonathan Dudley and Tseng, {Li Hui} and Lisa Rooper and Marco Harris and Lisa Haley and Guoli Chen and Christopher Gocke and James Eshleman and Ming-Tseh Lin",
year = "2015",
month = "2",
day = "1",
doi = "10.5858/arpa.2013-0649-OA",
language = "English (US)",
volume = "139",
pages = "211--218",
journal = "Archives of Pathology and Laboratory Medicine",
issn = "0003-9985",
publisher = "College of American Pathologists",
number = "2",

}

TY - JOUR

T1 - Challenges posed to pathologists in the detection of KRAS mutations in colorectal cancers

AU - Dudley, Jonathan

AU - Tseng, Li Hui

AU - Rooper, Lisa

AU - Harris, Marco

AU - Haley, Lisa

AU - Chen, Guoli

AU - Gocke, Christopher

AU - Eshleman, James

AU - Lin, Ming-Tseh

PY - 2015/2/1

Y1 - 2015/2/1

N2 - Context.-Detection of KRAS mutation is mandatory to predict response to anti-epidermal growth factor receptor monoclonal antibodies in patients with metastatic colorectal cancers. Objective.-To demonstrate challenges posed to pathologists in the clinical detection of KRAS mutations in colorectal cancers. Design.-In this retrospective analysis for quality assessment of the pyrosequencing assay, we survey the characteristics of 463 formalin-fixed, paraffin-embedded neoplastic tissues submitted for KRAS mutation detection during a 26-month period. Results.-The KRAS mutation was detected in 39.2% of tumors. This included 2 tumors with complex pyrograms (GGT>GAG at codon 12 and GGC>GTT at codon 13, as resolved by a Pyromaker software program) and 3 tumors with an indeterminate percentage of mutant alleles (defined as 4% to 5% and confirmed by a next-generation sequencing platform). Among the 25 specimens (5.5%) with fewer than 20% tumor cells, 22 were resected after chemotherapy/radiation. Significant depletion of tumor cells was observed in rectal cancers resected after neoadjuvant therapy (31.0%) versus those without previous treatment (0%) (P = .01). We also explore other specimens with low tumor cellularity and potential causes of discrepancy between the estimated tumor cell percentage and detected mutant allele frequency, such as intratumor heterogeneity of KRAS mutation. Conclusions.-Neoadjuvant therapy may deplete tumor cells and confound the molecular diagnosis of KRAS mutations. Accurate detection of specimens with poor tumor cellularity requires the appropriate selection of neoplastic tissues, evaluation of tumor cellularity, use of assays with high sensitivity, and prospective quality assessment.

AB - Context.-Detection of KRAS mutation is mandatory to predict response to anti-epidermal growth factor receptor monoclonal antibodies in patients with metastatic colorectal cancers. Objective.-To demonstrate challenges posed to pathologists in the clinical detection of KRAS mutations in colorectal cancers. Design.-In this retrospective analysis for quality assessment of the pyrosequencing assay, we survey the characteristics of 463 formalin-fixed, paraffin-embedded neoplastic tissues submitted for KRAS mutation detection during a 26-month period. Results.-The KRAS mutation was detected in 39.2% of tumors. This included 2 tumors with complex pyrograms (GGT>GAG at codon 12 and GGC>GTT at codon 13, as resolved by a Pyromaker software program) and 3 tumors with an indeterminate percentage of mutant alleles (defined as 4% to 5% and confirmed by a next-generation sequencing platform). Among the 25 specimens (5.5%) with fewer than 20% tumor cells, 22 were resected after chemotherapy/radiation. Significant depletion of tumor cells was observed in rectal cancers resected after neoadjuvant therapy (31.0%) versus those without previous treatment (0%) (P = .01). We also explore other specimens with low tumor cellularity and potential causes of discrepancy between the estimated tumor cell percentage and detected mutant allele frequency, such as intratumor heterogeneity of KRAS mutation. Conclusions.-Neoadjuvant therapy may deplete tumor cells and confound the molecular diagnosis of KRAS mutations. Accurate detection of specimens with poor tumor cellularity requires the appropriate selection of neoplastic tissues, evaluation of tumor cellularity, use of assays with high sensitivity, and prospective quality assessment.

UR - http://www.scopus.com/inward/record.url?scp=84921476538&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84921476538&partnerID=8YFLogxK

U2 - 10.5858/arpa.2013-0649-OA

DO - 10.5858/arpa.2013-0649-OA

M3 - Article

C2 - 25611103

AN - SCOPUS:84921476538

VL - 139

SP - 211

EP - 218

JO - Archives of Pathology and Laboratory Medicine

JF - Archives of Pathology and Laboratory Medicine

SN - 0003-9985

IS - 2

ER -