Letter to the Editor Mutational status of EGFR, BRAF, PI3KCA and JAK2 genes in endocrine tumors Nabahet Ameur 1 , Ludovic Lacroix 2 , Nelly Motte 2 , Eric Baudin 3 , Bernard Caillou 2 , Michel Ducreux 4 , Dominique Elias 5 , Philippe Chanson 6 , Martin Schlumberger 3 and Jean Michel Bidart 1,2 * 1 CNRS FRE 2939, Institut de Canc erologie Gustave-Roussy and University Paris-Sud 11, 94805 Villejuif, France 2 Translational Research Laboratory, Institut de Canc erologie Gustave-Roussy and University Paris-Sud 11, 94805 Villejuif, France 3 Department of Nuclear Medicine & Endocrine Oncology, Institut de Canc erologie Gustave-Roussy and University Paris-Sud 11, 94805 Villejuif, France 4 Gastroenterology Unit, Department of Medical Oncology, Institut de Canc erologie Gustave-Roussy and University Paris-Sud 11, 94805 Villejuif, France 5 Department of Surgical Oncology, Institut de Canc erologie Gustave-Roussy and University Paris-Sud 11, 94805 Villejuif, France 6 Department of Endocrinology, Hoˆpital de Biceˆtre, 94275 Le Kremlin-Biceˆtre, France Dear Sir, Endocrine tumors include thyroid tumors, adreno cortical tumors, neuroendocrine tumors (NET) of the respiratory tract and gastrointestinal system, parathyroid tumors, pituitary tumors and paragangliomas. 1 Although several genes involved in hereditary endocrine neoplasias have been identified, the mechanisms involved in tumorigenesis of sporadic NET remain largely unknown. 2–5 This is due to several limitations, including the variability in anatomic accessibility and the paucity of both human functional cell lines and relevant animal models. 6 Onco- gene mutations commonly encountered in non-endocrine tumors are rarely found in these tumors. However, growth factor receptor expression and activation together with somatostatin receptors are frequently involved in the development of NET. 4,7 Thus, the identification of novel genetic mutations can be help- ful for tumor diagnosis and classification, such as RET testing in MEN2, and may allow a better disease management. 5 Moreover, conventional cytotoxic chemotherapies are often poorly effective in the treatment of metastatic NET patients. 8 This observation supports the development of drug-targeted therapies, as exemplified by RET inhibitors in medullary and pap- illary thyroid carcinomas. 9,10 Indeed, attention is given to a range of genetic alterations in different signaling pathways, which con- stitute potential targets for drug-designed inhibitors. 10 Among these alterations, activating mutations in the serine/ threonine kinase BRAF gene have been described in a broad range of human cancers, including malignant melanomas, pap- illary thyroid carcinomas, ovarian and colon carcinomas. 11 Activating mutations of epidermal growth factor receptor (EGFR) have been found predictive of the efficacy of new compounds in lung adenocarcinomas. 12 The phosphatidylinosi- tol 3 0 -kinase (PI3K) pathway plays a major role in oncogenesis and somatic mutations within its PI3K catalytic subunit, PIK3ca, are frequently detected in solid tumors, 13 including as recently reported in poorly or undifferentiated thyroid carcino- mas. 14 Recently, dominant gain of function mutation V617F in the JAK2 gene pseudokinase domain (JH2) was identified in patients with myeloproliferative disorders. 15 Therefore, we decided to screen well-characterized muta- tions of EGFR, BRAF, PI3KCA and JAK2 genes in a large se- ries of thyroid carcinomas and NET samples (n 5 160) obtained from the Center for Biological Resources at Institut Gustave-Roussy. They included NET from the pancreas (n 5 11), small intestine (n 5 8), medullary thyroid carcinomas (n 5 25), paragangliomas (n 5 6), parathyroid tumors (n 5 4), pituitary adenomas (n 5 25), metastasis from unknown NET primitive tumor (n 5 2), differentiated thyroid tumors—hypo- functioning adenomas (n 5 13), papillary carcinomas (n 5 42), follicular carcinomas (n 5 6)—, adreno cortical carcino- mas (n 5 18) and corresponding tissues without any sign of malignancy (n 5 10) (Table I). Genomic DNA was isolated from tissue samples using TriReagent 1 (Sigma-Aldrich, St. Louis, MO) after histological control by an expert pathologist. DNA samples were screened for the V600E BRAF exon 15 mutation, the V617F JAK2 exon 12 mutation; for PI3KCA gene mutations in exon 9 (codons 539, 542, 545 and 546) and exon 20 (codons 1008, 1025, 1043, 1047 and 1049), 13,16,17 for EGFR exons 18 to 24 coding for ty- rosine kinase domain 18 and for RET exons 8, 10, 11, 13, 14, 15 and 16 mutations. Direct sequencing was performed, after PCR amplification of each exon, using the Big Dye Terminator sequencing kit (Applied Biosystems, Foster City, CA). The products were analyzed on an automated 3730 DNA Analyzer (Applied Biosystems). Sequence reading and alignment were performed with the SeqScape 1 software (Applied Biosys- tems). Fourteen of the 25 medullary thyroid carcinomas were he- reditary cases bearing germinal RET mutation at codons 611, 618, 634, 790 or 918. Furthermore, 3 of the 11 sporadic tumors presented a somatic RET mutation at codon 918. No V600E BRAF mutation was detected in hypofunctioning follicular adenomas, follicular carcinomas and non-tumoral contralateral thyroid tissues. In contrast, 22 of 42 (52%) tissues from papillary thyroid carcinomas were mutated. The V600E BRAF mutation was also observed in two tissue samples from gastroenteropancreatic (GEP) tumors: the first corresponded to a 31-year-old male patient presenting a 45-mm well-differenti- ated pancreatic tumor, with lymph node invasion but without Grant sponsors: CEA LRC-29V, Association pour la Recherche sur le Cancer, Ligue Nationale contre le Cancer. *Correspondence to: Institut de Canc erologie Gustave-Roussy, 39, rue Camille Desmoulins, 94805 Villejuif, France. Fax: 133-1-4211-5280. E-mail: bidart@igr.fr Received 21 April 2008; Accepted after revision 1 August 2008 DOI 10.1002/ijc.23999 Published online 15 September 2008 in Wiley InterScience (www.interscience. wiley.com). Int. J. Cancer: 124, 751–753 (2009) ' 2008 Wiley-Liss, Inc. Publication of the International Union Against Cancer