Predictive Impact of RNF43 Mutations in Patients With Proficient Mismatch Repair/Microsatellite Stable BRAFV600E-Mutated Metastatic Colorectal Cancer Treated With Target Therapy or Chemotherapy.

PURPOSE: Target therapy (TT) with encorafenib plus cetuximab is a standard option in patients with BRAFV600E-mutated (mut) pretreated metastatic colorectal cancer (mCRC). Recently, mutations in RNF43, encoding a negative regulator of the WNT pathway, were associated with longer progression-free survival (PFS) and overall survival (OS) in patients with proficient mismatch repair/microsatellite stable (pMMR/MSS) BRAFV600E-mut mCRC treated with TT. Here, we explored the effect of RNF43 mutations on the efficacy of second-line TT versus standard chemotherapy (CT). METHODS: A retrospective cohort of patients with pMMR/MSS BRAFV600E-mut tumors, available RNF43 mutational status, and treated with second-line TT or oxaliplatin- and/or irinotecan-based CT was analyzed. RESULTS: One hundred thirty-two patients with pMMR/MSS BRAFV600E-mut mCRC were included. RNF43 was found mut in 34 (26%) cases. Among RNF43 mutants, TT was associated with longer PFS (7.7 v 3.0 months; P = .002) and higher overall response rate (ORR; 45% v 0%; P = .009) compared with CT. Conversely, among RNF43 wild-type (wt) patients, only a trend for longer PFS (4.5 v 3.7 months; P = .064) favoring TT, with no differences in ORR (P = .14), was observed. After excluding 36 patients receiving TT in third line or beyond, a longer OS (19.4 v 10.1 months; P = .022) and a numerically OS advantage (10.6 v 6.6 months; P = .068) were reported for TT both in the RNF43-mut and in the RNF43 wt groups. However, no interaction effect was reported between RNF43 mutational status and treatment in ORR (Pinteraction = .96), PFS (Pinteraction = .13), and OS (Pinteraction = .44). CONCLUSION: Patients with pMMR/MSS BRAFV600E-mut mCRC achieve benefit from TT versus CT independently of RNF43 mutational status, although a higher magnitude of benefit from TT is observed in RNF43-mut tumors. These findings deserve confirmation in concluded and ongoing randomized trials.

Análise do gene AIP na acromegalia familial isolada / Analysis of the AIP gene in familial isolated acromegaly

A acromegalia é doença insidiosa e desfigurante caracterizada por um crescimento desproporcional dos ossos das mãos, pés e do crânio devido à exposição crônica a altos níveis de hormônio de crescimento (GH) e de seu efetor insuline growth factor 1 (IGF-1). Trata-se de uma doença rara, com incidência estimada de 3-4 casos por milhão, com prevalência de aproximadamente 50 casos por milhão de pessoas. A principal causa da acromegalia é a presença de um tumor hipofisário secretor de GH (somatotropinoma). Caso o somatotropinoma ocorra durante a infância ou adolescência, antes do fechamento das epífises dos ossos longos, a criança crescerá longitudinalmente de forma descontrolada, caracterizando a forma clínica gigantismo. Na grande maioria dos casos a acromegalia se apresenta na forma esporádica, entretanto casos familiais da doença podem ocorrer associados à Neoplasia Endócrina Múltipla tipo 1 (NEM-1), ao complexo de Carney (CNC) e à acromegalia familial isolada (IFS). Os genes responsáveis pela NEM-1 (MEN1) e CNC (PRKAR1A) foram clonados há mais 10 anos, entretanto etiologia molecular da IFS permaneceu desconhecida até recentemente. Vierimaa et al. (2006) combinaram estudos de ligação por análise de polimorfismos e estudos de expressão gênica e identificaram mutações no gene AIP em famílias com acromegalia não-NEM-1 e não-CNC; além de perda de heterozigose (LOH) nos somatotropinomas dos pacientes com mutação AIP. No presente estudo, investigamos o gene AIP em três famílias brasileiras com IFS e em seus tumores (hipofisários e não-hipofisários). Descrevemos uma nova mutação AIP (Y268X) em uma família brasileira com IFS, confirmando o papel desse novo gene na predisposição a tumores hipofisários. A partir de dados gerados em uma extensa revisão da literatura, sugerimos que os tumores hipofisários familiais isolados são doenças multigênicas que possuiriam um gene principal, mas que sofreriam influência de outros genes/loci ainda pouco caracterizados...

Acromegaly is a rare disfigurating and insidious disease characterized by enlargement of hands, feet and skull bones due to excess of growth hormone (GH) secreted by a pituitary tumor (somatotropinoma). The majority of the cases with acromegaly is sporadic, however it may occur in association with inherited disorders as Multiple Endocrine Neoplasia type 1 (MEN1), Carney complex (CNC) and Isolated Familial Somatotropinoma (IFS). The genes associated with MEN1 syndrome (MEN1) and CNC (PRKAR1A) have been described more than a decade ago, however until very recently the molecular etiology of IFS remained unknown. Using a combined strategy of single nucleotide polymorphism (SNP) analysis and gene expression analysis, Vierimaa et al. (2006) described mutations in the AIP gene occurring in families with acromegaly not associated with MEN1 and CNC. In the current study, we investigated three Brazilian families with IFS and were able to describe two germline mutations in the AIP gene, confirming the role of this new gene in the predisposition to familial somatotropinoma. We revised the literature of genetic studies of isolated pituitary adenoma syndromes, which indicated a genetic heterogeneity as well as possible multigenic inheritance for these diseases. Thus, we investigated the role of several genes/loci (SSTR2, SSTR5, CDKN1B, AHR, PRKAR1A, PTTG, PROP1, MEG3, RB1 and 2p16) selected as potentially acting as phenotypic modulators in IFS. Our data indicate that AIP-mutated patients are prone to pituitary disease, however it is necessary the co-segregation of markers located at oncogenic regions to the development of the pituitary tumors and manifestation of the disease. Herein, we also present the first somatic analysis of non-pituitary tumors of AIP-mutated patients. A potential role of AIP, which is implicated in the cAMP pathway, could not be excluded in the development of an adrenocortical carcinoma.

Screening of RET gene mutations in multiple endocrine neoplasia type-2 using Conformation Sensitive Gel Electrophoresis (CSGE)

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant inherited tumor syndrome caused by RET proto-oncogene germline mutations (RET). Here we tested the Conformation Sensitive Gel Electrophoresis (CSGE) as a screening method for RET hot-spot mutations. Seven MEN2 families were studied by direct sequencing analysis, CSGE and Single Strand Conformational Polymorphism (SSCP). Using CSGE/SSCP, we were able to detect four out of five types of RET mutations verified by sequencing analysis: Cys620Arg, Cys634Arg, Cys634Tyr, and Met918Thr, furthermore a missense substitution at codon 648 (Val648Ile). RET polymorphisms 691 and 769 were also verified. Data obtained using CSGE/SSCP were fully concordant. We conclude that CSGE showed to be a sensitive, fast, low-cost, and simple procedure to detect RET mutations in codons which are reported as the most prevalent RET variants (~ 95 percent) in large MEN2 series. As to the Val804Met mutation, this method still needs to be optimized.

A neoplasia endócrina múltipla tipo 2 (NEM2) é uma síndrome tumoral herdada por mutações germinativas no proto-oncogene RET (RET). Analisamos a aplicação do método Eletroforese em Gel Sensível à Conformação (CSGE) no rastreamento de mutações hot spots do RET. Sete famílias com NEM2 foram rastreadas pelo seqüenciamento gênico, CSGE e análise do Polimorfismo Conformacional de Cadeia Simples (SSCP). Usando ambas as metodologias de rastreamento, identificamos quatro dos cinco tipos de mutações verificadas pelo seqüenciamento: Cys620Arg, Cys634Arg, Cys634Tyr e Met918Thr, além da variação gênica Val648Ile. Das análises englobando mutações hot spots do RET, 90,6 por cento concordaram com o seqüenciamento genético (incluindo a variação gênica Val648Ile). Polimorfismos nos códons 691 e 769 foram documentados. Os dados obtidos por CSGE/SSCP foram totalmente concordantes. Concluímos que o CSGE revelou ser metodologia sensível, rápida, de fácil execução e baixo custo no rastreamento de mutações nos códons associados à grande maioria (~ 95 por cento) dos pacientes com NEM2.

Screening of RET gene mutations in multiple endocrine neoplasia type-2 using conformation sensitive gel electrophoresis (CSGE).

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant inherited tumor syndrome caused by RET proto-oncogene germline mutations (RET). Here we tested the Conformation Sensitive Gel Electrophoresis (CSGE) as a screening method for RET hot-spot mutations. Seven MEN2 families were studied by direct sequencing analysis, CSGE and Single Strand Conformational Polymorphism (SSCP). Using CSGE/SSCP, we were able to detect four out of five types of RET mutations verified by sequencing analysis: Cys620Arg, Cys634Arg, Cys634Tyr, and Met918Thr, furthermore a missense substitution at codon 648 (Val648Ile). RET polymorphisms 691 and 769 were also verified. Data obtained using CSGE/SSCP were fully concordant. We conclude that CSGE showed to be a sensitive, fast, low-cost, and simple procedure to detect RET mutations in codons which are reported as the most prevalent RET variants (approximately 95%) in large MEN2 series. As to the Val804Met mutation, this method still needs to be optimized.

[Genetic screening of multiple endocrine neoplasia type 2: experience of the USP Endocrine Genetics Unit]. / Rastreamento gênico da neoplasia endócrina múltipla tipo 2: experiência da Unidade de Endocrinologia Genética da USP.

Multiple endocrine neoplasia type 2 (MEN-2) is an inherited tumor syndrome that includes medullary thyroid carcinoma (MTC), primary hyperparathyroidism, pheochromocytoma and other non-endocrine diseases. Since the first RET missense mutations in association with MEN-2 were identified, RET mutation analysis had a great impact in the clinical management of MEN-2, such as in early diagnosis and treatment of MTC. Presently, early total thyroidectomy provides real cure of MTC for cases in which molecular diagnosis has been performed at early ages. After RET mutation identification, family members should be screened for this mutation by using methods as DGGE, SSCP, restriction enzyme, genetic sequencing or mini-sequencing. In this paper, we briefly review our experience with the direct RET gene sequencing and DGGE approaches. In 50 typical MEN-2 patients analyzed using both methods, we found no false results suggesting that DGGE is a reliable screening method for RET proto-oncogene mutation analysis.

Impact of RET proto-oncogene analysis on the clinical management of multiple endocrine neoplasia type 2.

Multiple endocrine neoplasia type 2 (MEN2) is an autosomal dominant disease characterized by the presence of medullary thyroid carcinoma, primary hyperparathyroidism, and pheochromocytoma. Multiple endocrine neoplasia type 2 is still an underdiagnosed, or late-diagnosed condition in many areas of the world. Since 1993, when the first missense RET proto-oncogene (RET) mutations were reported in MEN2, up to 46 different RET-causing disease mutations have been described. Since a strong genotype-phenotype correlation exists for MEN2, the detection of RET mutations has produced a major impact in early recognition and treatment of MTC and MEN2. Presently, RET mutation analysis should be performed for all MEN2 cases and their at-risk familial relatives. Further, prophylactic total thyroidectomy is indicated in all cases harboring activating gametic RET mutations. In most RET mutation carriers, prophylactic total thyroidectomy is indicated at ages as early as a few months to 4 years of age, promoting longer survival and improvement of quality of life or even definitive cure. We discuss the large impact of RET proto-oncogene analysis on the clinical management of MEN2 and the role of early RET molecular DNA diagnosis in providing clinicians and surgeons with valuable information that enables them to indicate early total thyroidectomy.

Impact of RET proto-oncogene analysis on the clinical management of multiple endocrine neoplasia type 2

A neoplasia endócrina múltipla tipo 2 (NEM2) é caracterizada pela ocorrência do carcinoma medular de tireóide (CMT), hiperparatiroidismo primário (HPT) e feocromocitoma (FEO).1-12 Desde 1993, quando as primeiras mutações do tipo missense no proto-oncogene RET (RET), associadas a NEM2 foram identificadas, 46 diferentes mutações causadoras de doenças foram descritas.13-17 Como há uma forte correlação genótipo-fenótipo na NEM2, a detecção de mutações no RET adquiriu grande impacto no tratamento precoce do CMT e NEM2. A NEM2 persiste como uma doença subdiagnosticada e/ou tardiamente diagnosticada em várias áreas geográficas do globo. A análise de mutações do RET deve ser realizada em todas os casos de NEM2 e atualmente, a tireoidectomia total profilática é indicada para todos os indivíduos portadores de mutações no RET.1 Para a grande maioria dos portadores de mutações gaméticas ativadoras no RET este procedimento cirúrgico é indicado nos primeiros anos de vida, promovendo melhora na qualidade de vida, aumento da sobrevida ou mesmo levando à cura definitiva.1 Discutimos nesta revisão, o impacto da análise do proto-oncogene RET na conduta clínica da neoplasia endócrina múltipla tipo 2. Além disso, o diagnóstico molecular do RET fornece à clínicos e cirurgiões a mais valiosa das informações, permitindo indicação de tireoidectomia total profilática.

Rastreamento gênico da neoplasia endócrina múltipla tipo 2: experiência da Unidade de Endocrinologia Genética da USP / Genetic screening of multiple endocrine neoplasia type 2: experience of the USP Endocrine Genetics Unit

A neoplasia endócrina múltipla tipo 2 (NEM-2) é uma síndrome tumoral hereditária que compreende: carcinoma medular de tireóide, hiperparatiroidismo primário, feocromocitoma e outras doenças não-endócrinas. Desde a identificação das primeiras mutações missense no RET associadas ao NEM-2, a detecção de mutações no RET adquiriu grande impacto no tratamento clínico da NEM-2, tais como o pronto diagnóstico e tratamento do CMT. Atualmente a tireoidectomia total possibilita real cura dos casos de CMT nos quais os diagnósticos moleculares foram efetuados precocemente. Depois de identificadas as mutações no RET, os demais familiares devem ser rastreados para esta mutação utilizando-se métodos como DGGE, SSCP, enzima de restrição, seqüenciamento e mini-seqüenciamento gênico. Apresentamos uma breve revisão da nossa experiência com seqüenciamento gênico direto do RET e DGGE. Em 50 pacientes com NEM-2 analisados por ambas as técnicas, não encontramos falsos resultados, sugerindo que o DGGE é uma metodologia de rastreamento adequada para mutações no proto-oncogene RET.