ADVANCES IN TECHNOLOGY Section Editor: Ben Davidson, M.D., Ph.D. KRAS Testing on Colo-Rectal Carcinoma Cytological Imprints Umberto Malapelle, B.S., 1 Claudio Bellevicine, M.D., 1 Anna Russo, M.D., 1 Maria Salatiello, B.S., 1 Lucio Palombini, M.D., Ph.D., 1 and Giancarlo Troncone, M.D., Ph.D. 1,2 * Anti-EGFR monoclonal antibodies, cetuximab, and panitumu- mab, are administrated under the condition that advanced colo- rectal cancer (CRC) carries a wild-type KRAS gene. Thus, clini- cians request pathologists to genotype KRAS before treatment. In the near future routine mutation testing at the same time of the surgery may be implemented. The reliability of a rapid KRAS test- ing on ex vivo cytological samples obtained by direct scraping of the colon tumour tissue is here evaluated. A consecutive series of 20 surgically resected, primary CRC specimens was analysed. Fresh tissue from CRC was scraped with a scalpel blade, smeared on uncoated glass slides, air-dried and Diff–Quik stained to ensure malignant cell presence. The same tissue area was also histologically processed. Exon 2 KRAS gene mutations were evaluated on both cytological and histological specimens by dideoxy sequencing and by the DxS KRAS Mutation Test Kit (DxS, Manchester, England). Data obtained on on imprint cy- tology and matched histological samples showed full concord- ance; however, the mutation frequency was slightly higher (35%) by the DxS KRAS Mutation Test Kit than by the dideoxy sequencing (30%). Thus, colon cancer imprint cytology sample is a reliable biospecimen for both dideoxy-sequencing and DxS KRAS Mutation Test Kit analysis and it may be useful to abbreviate the KRAS assay turnaround time. Diagn. Cytopa- thol. 2011;39:274–277. ' 2010 Wiley-Liss, Inc. Key Words: colo-rectal cancer; KRAS; polymnerase chain reaction; imprints; cytology The epidermal growth factor receptor (EGFR), a HER fam- ily receptor tyrosine kinase, is a main target in cancer ther- apy. 1 Anti-EGFR monoclonal antibodies, cetuximab, and panitumumab, that competitively inhibit the binding of the ligands to the extracellular domain of the receptor, are cur- rently widespread used for the treatment of advanced colo- rectal cancer (CRC). 1 However, only a small minority of CRC patients is responsive to EGFR targeted therapies. 2 The identification of those patients who will really benefit from this treatment, would limit toxicities, treatment delays, and health care costs. 3 In this respect, mutations of the KRAS oncogene result in the constitutive activation of the EGFR signaling pathway. This renders attempts of EGFR blocking in vain; 2 thus, cetuximab and panitumumab, have been labelled for use in metastatic CRC under the condition that the tumor carries a wild-type KRAS gene. 4 In the current clinical setting, CRC surgical samples are not routinely assessed for KRAS mutations. 4 Clinicians request pathologists to genotype KRAS only when consider- ing anti-EGFR treatment. Upon the specific request of the clinician, pathologists find the tissue block containing the tu- mor area of interest; then, DNA extraction and KRAS muta- tion analysis are performed. However, the process of request- ing KRAS status testing, retrieving the original tissue block and reporting the test results is burdensome, time-consuming, and likely to errors. 5 Therefore, routine mutation testing at the same time of the surgery can enhance the standard of patient care. In such a prospective, to abbreviate turnaround time assay, ex vivo cytological samples rather than formalin- fixed paraffin-embedded (FFPE) tumor tissue blocks could be employed. Imprints can easily be obtained at the time of the gross examination of the resected specimen by direct tissue scraping; the need of histological processing is obvi- ated as DNA can be extracted, immediately after that ma- lignant cells have been visualized by Diff–Quik (D–Q) staining. Thus histology and molecular pathology labs could work concurrently to issue a single report, that will include both morphological and molecular assessments. Currently, direct dideoxy-sequencing technique is adopted for KRAS testing by most laboratories. 3 However, 1 Dipartimento di Scienze Biomorfologiche e Funzionali, Universita ` di Napoli Federico II, Naples, Italy 2 CEINGE-Biotecnologie Avanzate, Naples, Italy Grant sponsor: Regione Campania ‘‘Nuovi marcatori molecolari nella diagnosi citologica’’ grant. *Correspondence to: Giancarlo Troncone, M.D., Ph.D., Dipartimento di Scienze Biomorfologiche e Funzionali, Universita ` di Napoli Federico II, via Sergio Pansini 5, I-80131 Napoli, Italy. E-mail: giancarlo.troncone@unina.it Received 29 December 2009; Accepted 18 March 2010 DOI 10.1002/dc.21417 Published online 6 July 2010 in Wiley Online Library (wileyonlinelibrary.com). 274 Diagnostic Cytopathology, Vol 39, No 4 ' 2010 WILEY-LISS, INC.