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PURPOSE: HER2-targeted therapies have dramatically improved outcomes of patients with HER2-positive breast cancer (BC), as demonstrated in neoadjuvant trials. This study aims to provide real-world evidence on the use and effectiveness of combined pertuzumab, trastuzumab and chemotherapy (CT) in early-stage HER2-positive BC. METHODS: A retrospective, multicentre study was conducted on patients diagnosed with HER2-positive early BC treated with neoadjuvant pertuzumab and trastuzumab plus CT at 13 Spanish sites. The primary endpoint was pathological complete response (pCR). RESULTS: A total of 310 patients were included. Pertuzumab and trastuzumab were combined with anthracyclines and taxanes, carboplatin and docetaxel, and taxane-based CT in 77.1%, 16.5%, and 6.5% of patients, respectively. Overall, the pCR rate was 62.2%. The pCR was higher amongst patients with hormone receptor-negative tumours and with tumours expressing higher levels of Ki-67 (> 20%). After postoperative adjuvant treatment, 13.9% of patients relapsed. Those patients who did not achieve pCR, with tumours at advanced stages (III), and with node-positive disease were more likely to experience distant relapse. Median overall survival (OS) and distant disease-free survival (D-DFS) were not reached at the study end. The estimated mean OS and D-DFS times were 7.5 (95% CI 7.3-7.7) and 7.3 (95% CI 7.1-7.5) years, respectively (both were significantly longer amongst patients who achieved pCR). Grade 3-4 anti-HER2 related toxicities were reported in six (1.9%) patients. CONCLUSION: Neoadjuvant pertuzumab and trastuzumab plus CT achieve high pCR rates in real-life patients with HER2-positive early BC, showing an acceptable safety profile. Innovative adjuvant strategies are essential in patients at high risk of distant disease recurrence.
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Anticuerpos Monoclonales Humanizados , Protocolos de Quimioterapia Combinada Antineoplásica , Neoplasias de la Mama , Terapia Neoadyuvante , Receptor ErbB-2 , Trastuzumab , Humanos , Femenino , Neoplasias de la Mama/tratamiento farmacológico , Neoplasias de la Mama/patología , Neoplasias de la Mama/metabolismo , Trastuzumab/uso terapéutico , Trastuzumab/administración & dosificación , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Persona de Mediana Edad , Estudios Retrospectivos , Receptor ErbB-2/metabolismo , Anticuerpos Monoclonales Humanizados/uso terapéutico , Anticuerpos Monoclonales Humanizados/administración & dosificación , Adulto , Anciano , Carboplatino/administración & dosificación , Carboplatino/uso terapéutico , Taxoides/administración & dosificación , Taxoides/uso terapéutico , Docetaxel/administración & dosificación , Docetaxel/uso terapéutico , Estadificación de NeoplasiasRESUMEN
PURPOSE: Tri-weekly carboplatin is an established neoadjuvant treatment for triple-negative breast cancer, enhancing pathological complete response (pCR) and overall survival. This study explores if weekly carboplatin provides lower toxicity and comparable pCR rates. METHODS/PATIENTS: A retrospective multicenter study (January 2021 to March 2023) compares outcomes of weekly and tri-weekly carboplatin. RESULTS: Among 104 participants, 60% received weekly and 40% tri-weekly treatments. Weekly administration had fewer discontinuations (56.5 vs. 70.7%, p = 0.154). Both schedules exhibited similar overall toxicity (p = 0.087), with slightly higher grade 3-4 toxicity in the tri-weekly group (56.1 vs. 48.4%, p = 0.126). Hematological toxicity was comparable, but the weekly group experienced more diarrhea (p = 0.432) and asthenia (p = 0.012). Weekly treatment correlated with more frequent breast-conserving surgeries (p = 0.004). pCR rates were 50% with weekly and 61% with tri-weekly regimens (p = 0.186). CONCLUSIONS: Weekly carboplatin exhibited comparable toxicity, a trend toward fewer interruptions, and similar pCR rates. Prospective studies are essential for validating these findings.
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Carboplatino , Esquema de Medicación , Terapia Neoadyuvante , Neoplasias de la Mama Triple Negativas , Humanos , Carboplatino/administración & dosificación , Carboplatino/efectos adversos , Estudios Retrospectivos , Femenino , Neoplasias de la Mama Triple Negativas/tratamiento farmacológico , Neoplasias de la Mama Triple Negativas/patología , Persona de Mediana Edad , Adulto , Anciano , Antineoplásicos/uso terapéutico , Antineoplásicos/administración & dosificación , Antineoplásicos/efectos adversosRESUMEN
Soft tissue sarcomas (STS) are an uncommon and biologically heterogeneous group of tumors arising from mesenchymal cells. The incidence is estimated at five cases per 100,000 people per year. Retroperitoneal sarcomas (RPS) account for 10-15% of all STS, and their management depends on their anatomical characteristics and histotype. Due to their very low incidence, it is recommended that RPS be treated in reference centers and evaluated by an experienced multidisciplinary team (MDT). In Spain, the Spanish Group for Research in Sarcomas (GEIS) brings together experts from various specialties to promote research on sarcomas and improve treatment results. This paper summarizes the GEIS recommendations for the diagnosis, treatment, and follow-up of patients with RPS.
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Importance: Preclinical data about the synergistic activity of radiotherapy (RT) and trabectedin have been reported. The combination of trabectedin and RT in treating myxoid liposarcomas appears worth exploring. Objective: To explore the effectiveness and safety of trabectedin combined with RT. Design, Setting, and Participants: This international, open-label, phase 2 nonrandomized clinical trial including 46 patients with myxoid liposarcoma was conducted in 4 centers in Spain, 1 in Italy, and 2 in France from July 1, 2016, to September 30, 2019. Eligible patients had to have a histologic, centrally reviewed diagnosis of localized resectable myxoid liposarcoma arising from an extremity or the trunk wall. Interventions: Trabectedin was administered at the recommended dose stemming from the phase 1 trial (1.5 mg/m2), with intravenous infusion during 24 hours every 21 days for a total of 3 cycles. Radiotherapy was started after completion of the first trabectedin infusion (cycle 1, day 2). Patients received 25 fractions of radiation for a total of 45 Gy. Surgery was planned 3 to 4 weeks after the administration of the last preoperative cycle and not until 4 weeks after the end of preoperative RT. Pathologic specimens were mapped in tumor sections to estimate the histologic changes and the percentage of viable tumor after neoadjuvant treatment. Main Outcomes and Measures: The primary objective of the phase 2 part of the study was overall response. Secondary objectives were effectiveness measured by relapse-free survival and activity measured by functional imaging and pathologic response. Results: A total of 46 patients were enrolled. Four patients were not evaluable. The median age was 43 years (range, 18-77 years), and 31 patients were male (67%). Overall, 9 of 41 patients (22%) achieved a partial response with neoadjuvant treatment with trabectedin and RT, with 5 of 39 patients (13%) achieving a complete pathologic response and 20 of 39 patients (51%) having 10% or less of a viable remaining tumor. Partial responses according to Choi criteria were observed in 24 of 29 evaluable patients (83%), and no patient had disease progression. Treatment was well tolerated. Conclusions and Relevance: Although the primary end point of this phase 2 nonrandomized clinical trial was not met (Response Evaluation Criteria in Solid Tumors response in ≥70% of patients), results suggest this combination was well tolerated and effective in terms of pathologic response. Thus, trabectedin plus RT might be a treatment option regarding tolerability; further evidence should be generated in this setting.
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Liposarcoma Mixoide , Sarcoma , Neoplasias de los Tejidos Blandos , Adulto , Humanos , Masculino , Femenino , Trabectedina/efectos adversos , Trabectedina/administración & dosificación , Liposarcoma Mixoide/tratamiento farmacológico , Liposarcoma Mixoide/radioterapia , Antineoplásicos Alquilantes/efectos adversos , Antineoplásicos Alquilantes/administración & dosificación , Recurrencia Local de Neoplasia/tratamiento farmacológico , Sarcoma/tratamiento farmacológico , Neoplasias de los Tejidos Blandos/tratamiento farmacológicoRESUMEN
Pazopanib was assessed prospectively in the GEIS-32 phase II study (NCT02066285) on advanced solitary fibrous tumour (SFT), resulting in a longer progression-free survival (PFS) and overall survival (OS) compared with historical controls treated with chemotherapy. A retrospective analysis of peripheral inflammatory indexes in patients enrolled into GEIS-32 was performed to evaluate their prognostic and predictive value. Patients received pazopanib 800 mg/day as the first antiangiogenic line. The impacts of baseline neutrophil/lymphocyte ratio (NLR), platelet/lymphocyte ratio (PLR), and red cell distribution width (RDW) on PFS, OS, and Choi response were evaluated by univariate and multivariate analysis. Metastasis-free interval (MFI), mitotic count, and ECOG were also included as potential prognostic factors. Sixty-seven SFT patients, enrolled in this study, showed a median age of 63 years and a female/male distribution of 57/43. The median follow-up from treatment initiation was 16.8 months. High baseline NLR, PLR, and standardised RDW were significantly associated with worse PFS and OS. NLR, RDW, MFI, and mitotic count were independent variables for PFS, while RDW and ECOG were independent for OS. Further, NLR and mitotic count were independent factors for Choi response. High baseline NLR and RDW values were independent prognostic biomarkers for worse outcome in advanced SFT patients treated with pazopanib.
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The PANGEA-Breast trial evaluated a new chemo-immunotherapeutic combination that would synergistically induce long-term clinical benefit in HER2-negative advanced breast cancer patients. Treatment consisted of 21-day cycles of 200 mg of pembrolizumab (day 1) plus gemcitabine (days 1 and 8). The primary objective was the objective response rate (ORR). The tumor infiltrating lymphocytes (TILs) density and PD-L1 expression in tumor, and the myeloid-derived suppressor cells (MDSCs) level in peripheral blood, were analyzed to explore associations with treatment efficacy. Considering a two-stage Simon's design, the study recruitment was stopped after its first stage as statistical assumptions were not met. A subset of 21 triple-negative breast cancer (TNBC) patients was enrolled. Their median age was 49 years; 15 patients had visceral involvement, and 16 had ≤3 metastatic locations. Treatment discontinuation due to progressive disease (PD) was reported in 16 patients. ORR was 15% (95% CI 3.2-37.9). Four patients were on treatment >6 months before PD. Grade ≥3 treatment-related adverse events were observed in 8 patients, where neutropenia was the most common. No association was found between TILs density, PD-L1 expression or MDSCs levels and treatment efficacy. ORR in TNBC patients also did not meet the assumptions, but 20% were on treatment >6 months.
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Among all Soft Tissue sarcomas there are some subtypes with low incidence and/or peculiar clinical behaviour, that need to be consider separately. Most of them are orphan diseases, whose biological characteristics imply a clearly different diagnostic and therapeutic approach from other more common sarcoma tumors. We present a brief and updated multidiciplinary review, focused on practical issues, aimed at helping clinicians in decision making. In this second part we review these subtypes: Alveolar Soft Part Sarcoma, Epithelioid Sarcoma, Clear Cell Sarcoma, Desmoplastic Small Round Cell Tumor, Rhabdoid Tumor, Phyllodes Tumor, Tenosynovial Giant Cell Tumors, Myoepithelial Tumor, Perivascular Epithelioid Cell Neoplasms (PEComas), Extraskeletal Myxoid Chondrosarcoma, NTRK-fusions Sarcomas. Most of them present their own radiological and histopathological feautures, that are essential to know in order to achieve early diagnosis. In some of them, molecular diagnosis is mandatory, not only in the diagnosis, but also to plan the treatment. On the other hand, and despite the low incidence, a great scientific research effort has been made to achieve new treatment opportunities for these patients even with approved indications. These include new treatments with targeted therapies and immunotherapy, which today represent possible therapeutic options. It is especially important to be attentive to new and potential avenues of research, and to promote the conduct of specific clinical trials for rare sarcomas.
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Sarcoma/diagnóstico , Sarcoma/terapia , Neoplasias de los Tejidos Blandos/diagnóstico , Neoplasias de los Tejidos Blandos/terapia , Toma de Decisiones , Humanos , Guías de Práctica Clínica como AsuntoRESUMEN
The aim of this study was to identify an easily reliable prognostic score that selects the subset of advanced soft tissue sarcoma (ASTS) patients with a higher benefit with trabectedin in terms of time to progression and overall survival. A retrospective series of 357 patients with ASTS treated with trabectedin as second- or further-line in 19 centers across Spain was analyzed. First, it was confirmed that patients with high growth modulation index (GMI > 1.33) were associated with the better clinical outcome. Univariate and multivariate analyses were performed to identify factors associated with a GMI > 1.33. Thus, GEISTRA score was based on metastasis free-interval (MFI ≤ 9.7 months), Karnofsky < 80%, Non L-sarcomas and better response in the previous systemic line. The median GMI was 0.82 (0-69), with 198 patients (55%) with a GMI < 1, 41 (11.5%) with a GMI 1-1.33 and 118 (33.1%) with a GMI > 1.33. The lowest GEISTRA score showed a median of time-to-progression (TTP) and overall survival (OS) of 5.7 and 19.5 months, respectively, whereas it was 1.8 and 3.1 months for TTP and OS, respectively, for the GEISTRA 4 score. This prognostic tool can contribute to better selecting candidates for trabectedin treatment in ASTS.
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Importance: Active therapeutic combinations, such as trabectedin and radiotherapy, offer potentially higher dimensional response in second-line treatment of advanced soft-tissue sarcomas. Dimensional response can be relevant both for symptom relief and for survival. Objective: To assess the combined use of trabectedin and radiotherapy in treating patients with progressing metastatic soft-tissue sarcomas. Design, Setting, and Participants: Phase 1 of this nonrandomized clinical trial followed the classic 3 + 3 design, with planned radiotherapy at a fixed dose of 30 Gy (3 Gy/d for 10 days) and infusion of trabectedin at 1.3 mg/m2 as the starting dose, 1.5 mg/m2 as dose level +1, and 1.1 mg/m2 as dose level -1. Phase 2 followed the Simon optimal 2-stage design. Allowing for type I and II errors of 10%, treatment success was defined as an overall response rate of 35%. This study was conducted in 9 sarcoma referral centers in Spain, France, and Italy from April 13, 2015, to November 20, 2018. Adult patients with progressing metastatic soft-tissue sarcoma and having undergone at least 1 previous line of systemic therapy were enrolled. In phase 2, patients fitting inclusion criteria and receiving at least 1 cycle of trabectedin and the radiotherapy regimen constituted the per-protocol population; those receiving at least 1 cycle of trabectedin, the safety population. Interventions: Trabectedin was administered every 3 weeks in a 24-hour infusion. Radiotherapy was required to start within 1 hour after completion of the first trabectedin infusion (cycle 1, day 2). Main Outcomes and Measures: The dose-limiting toxic effects of trabectedin (phase 1) and the overall response rate (phase 2) with use of trabectedin plus irradiation in metastatic soft-tissue sarcomas. Results: Eighteen patients (11 of whom were male) were enrolled in phase 1, and 27 other patients (14 of whom were female) were enrolled in phase 2. The median ages of those enrolled in phases 1 and 2 were 42 (range, 23-74) years and 51 (range, 27-73) years, respectively. In phase 1, dose-limiting toxic effects included grade 4 neutropenia lasting more than 5 days in 1 patient at the starting dose level and a grade 4 alanine aminotransferase level increase in 1 of 6 patients at the +1 dose level. In phase 2, among 25 patients with evaluable data, the overall response rate was 72% (95% CI, 53%-91%) for local assessment and 60% (95% CI, 39%-81%) for central assessment. Conclusions and Relevance: The findings of this study suggest that the recommended dose of trabectedin for use in combination with this irradiation regimen is 1.5 mg/m2. The trial met its primary end point, with a high overall response rate that indicates the potential of this combination therapy for achieving substantial tumor shrinkage beyond first-line systemic therapy in patients with metastatic, progressing soft-tissue sarcomas. Trial Registration: ClinicalTrials.gov Identifier: NCT02275286.
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Sarcoma/tratamiento farmacológico , Sarcoma/radioterapia , Trabectedina/administración & dosificación , Adulto , Anciano , Terapia Combinada , Supervivencia sin Enfermedad , Relación Dosis-Respuesta a Droga , Relación Dosis-Respuesta en la Radiación , Femenino , Francia/epidemiología , Humanos , Italia/epidemiología , Masculino , Persona de Mediana Edad , Metástasis de la Neoplasia , Sarcoma/patología , España/epidemiología , Trabectedina/efectos adversosRESUMEN
Background: Subcutaneous trastuzumab (T-SC) administration does not allow the historical target concentration of 20 µg/mL for efficacy to be reached, from the start of treatment in patients with a body mass index (BMI) >30 kg/m2. Objectives: To analyze the influence of the strategy of dosification (fixed vs adjusted patient's body weight dose) on the initial minimum plasma concentration (Cmin) of trastuzumab in obese patients. Methods: This was an observational, prospective study, which included patients with HER2-positive nonmetastatic breast cancer treated with trastuzumab. The determination of the Cmin of trastuzumab was performed on day +21 of the first cycle using the ELISA technique. Patients were stratified according to the strategy of dosification and BMI. Results: A total of 50 patients were included; 16 patients received the drug intravenously and 34 in a fixed dosage subcutaneous (T-SC) regimen. The proportion of patients who achieved an adequate plasma concentration since the beginning of treatment was significantly higher when the drug was administered intravenously (93.8% vs 67.6%, P = 0.042). These differences are especially greater in T-SC patients with BMI >30 kg/m2, with only 20% of patients exceeding the pharmacokinetic target. Conclusion and Relevance: Our study suggests that trastuzumab SC fixed dose of 600 mg is not equivalent to IV administration, especially in obese patients. An adequate trastuzumab exposure in this population needs patient weight-adjusted IV dosage in the first administration. The clinical relevance of these findings remains to be elucidated, and further research, including larger controlled trials, is warranted.
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Antineoplásicos Inmunológicos/administración & dosificación , Antineoplásicos Inmunológicos/sangre , Neoplasias de la Mama/tratamiento farmacológico , Obesidad/sangre , Trastuzumab/administración & dosificación , Trastuzumab/sangre , Administración Intravenosa , Adulto , Antineoplásicos Inmunológicos/uso terapéutico , Índice de Masa Corporal , Peso Corporal , Neoplasias de la Mama/sangre , Neoplasias de la Mama/complicaciones , Femenino , Humanos , Infusiones Intravenosas , Inyecciones Subcutáneas , Persona de Mediana Edad , Obesidad/complicaciones , Obesidad/tratamiento farmacológico , Estudios Prospectivos , Receptor ErbB-2/antagonistas & inhibidores , Trastuzumab/uso terapéuticoRESUMEN
Soft tissue sarcomas (STS) constitute a heterogeneous group of rare solid tumors associated with significant morbidity and mortality. The evaluation and treatment of STS require a multidisciplinary team with extensive experience in the management of these types of tumors. National and international clinical practice guidelines for STS do not always provide answers to a great many situations that specialists have to contend with in their everyday practice. This consensus provides a series of specific recommendations based on available scientific evidence and the experience of a group of experts to assist in decision-making by all the specialists involved in the management of STS.
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Sunitinib is the currently standard treatment for metastatic renal cell carcinoma (mRCC). Multiple candidate predictive biomarkers for sunitinib response have been evaluated but none of them has been implemented in the clinic yet. The aim of this study was to analyze single nucleotide polymorphisms (SNPs) in genes linked to mode of action of sunitinib and immune response as biomarkers for mRCC. This is a multicenter, prospective and observational study involving 20 hospitals. Seventy-five mRCC patients treated with sunitinib as first line were used to assess the impact of 63 SNPs in 31 candidate genes on clinical outcome. rs2243250 (IL4) and rs5275 (PTGS2) were found to be significantly associated with shorter cancer-specific survival (CSS). Moreover, allele C (rs5275) was associated with higher PTGS2 expression level confirming its functional role. Combination of rs5275 and rs7651265 or rs2243250 for progression free survival (PFS) or CSS, respectively, was a more valuable predictive biomarker remaining significant after correction for multiple testing. It is the first time that association of rs5275 with survival in mRCC patients is described. Two-SNP models containing this functional variant may serve as more predictive biomarkers for sunitinib and could suppose a clinically relevant tool to improve the mRCC patient management.
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Biomarcadores de Tumor/genética , Carcinoma de Células Renales/tratamiento farmacológico , Carcinoma de Células Renales/genética , Ciclooxigenasa 2/genética , Indoles/uso terapéutico , Neoplasias Renales/tratamiento farmacológico , Neoplasias Renales/genética , Polimorfismo de Nucleótido Simple/genética , Pirroles/uso terapéutico , Adulto , Anciano , Anciano de 80 o más Años , Supervivencia sin Enfermedad , Femenino , Frecuencia de los Genes/genética , Estudios de Asociación Genética , Humanos , Indoles/farmacología , Estimación de Kaplan-Meier , Masculino , Persona de Mediana Edad , Modelos Genéticos , Análisis Multivariante , Pirroles/farmacología , Sunitinib , Resultado del TratamientoRESUMEN
INTRODUCCIÓN: Los tumores estromales gastrointestinales (GIST) son los tumores mesenquimales más frecuentes del tracto gastrointestinal. Han surgido numerosas publicaciones de GIST asociados con otras neoplasias. OBJETIVOS: El objetivo de este estudio fue investigar esta posible asociación en una población aislada genéticamente. MÉTODOS: Se realizó un estudio retrospectivo de pacientes con GIST en nuestro centro entre los años 2002-2009. Se compararon datos epidemiológicos, patológicos y familiares de pacientes con GIST sin neoplasias asociadas (grupo A) frente a pacientes con GIST y neoplasias asociadas (grupo B). Se investigó un posible mecanismo genético común entre GIST y las neoplasias asociadas mediante la detección, en todos los tumores, por el marcador inmunohistoquímico CD117. RESULTADOS: Se hallaron 22 pacientes con GIST, 10 del grupo A (45%) y 12 del grupo B (55%). En el grupo B, el tumor asociado fue maligno en 6 pacientes (50%) y benigno en otros 6 (50%). De 22 pacientes con GIST, 8 (36%) presentaron antecedentes familiares de neoplasia maligna. De estos 8 pacientes, 7 eran (87,5%) del grupo B (p = 0,03) y en 3 (37,5%) coincidieron el tipo anatomopatológico de neoplasia padecida por el paciente y su familiar. No hubo GIST en ningún familiar. Todos los GIST mostraron positividad para el CD117, mientras que las neoplasias asociadas fueron negativas para este marcador. CONCLUSIONES: No se ha demostrado positividad inmunohistoquímica para CD117 en las neoplasias asociadas. Dadas las especiales características de la población a estudio, la relación entre GIST y las neoplasias asociadas posiblemente sea casual
INTRODUCTION: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. Numerous studies have reported the association between GIST and other neoplasms. OBJECTIVES: The aim of this study was to investigate the possible association between GIST and other tumors in a genetically isolated population. METHODS: A retrospective study was conducted of patients with GIST between 2002 and 2009 at our center. Epidemiological, pathological and family data in patients with GIST alone (group A) were compared with those in patients with GIST associated with other neoplasms (group B). A possible common genetic mechanism was investigated between GIST and associated malignancies by testing the detection of the immunohistochemical marker, CD117, in all tumors. RESULTS: Twenty-two patients with GIST were identified, 10 in group A (45%) and 12 in group B (55%). In group B, the associated tumor was malignant in 6 patients (50%) and benign in another 6 (50%). Of the 22 patients with GIST, 8 (36%) had a family history of malignancies. Of these 8 patients, 7 (87.5%) were in group B (p = 0.03) and 3 (37.5%) showed the same pathological type of neoplasm as their relatives. All GIST were positive for CD117 whereas associated malignancies were negative for this marker. CONCLUSION: We did not find immunohistochemical positivity for CD117 in malignancies associated with GIST. Given the special characteristics of the study population, the association between GIST and associated malignancies may be incidental
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Humanos , Tumores del Estroma Gastrointestinal/genética , Proteínas Proto-Oncogénicas c-kit/análisis , Neoplasias Gastrointestinales/genética , Marcadores Genéticos , Predisposición Genética a la Enfermedad , Neoplasias Primarias Secundarias/genéticaRESUMEN
INTRODUCTION: Gastrointestinal stromal tumors (GIST) are the most common mesenchymal tumors of the gastrointestinal tract. Numerous studies have reported the association between GIST and other neoplasms. OBJECTIVES: The aim of this study was to investigate the possible association between GIST and other tumors in a genetically isolated population. METHODS: A retrospective study was conducted of patients with GIST between 2002 and 2009 at our center. Epidemiological, pathological and family data in patients with GIST alone (group A) were compared with those in patients with GIST associated with other neoplasms (group B). A possible common genetic mechanism was investigated between GIST and associated malignancies by testing the detection of the immunohistochemical marker, CD117, in all tumors. RESULTS: Twenty-two patients with GIST were identified, 10 in group A (45%) and 12 in group B (55%). In group B, the associated tumor was malignant in 6 patients (50%) and benign in another 6 (50%). Of the 22 patients with GIST, 8 (36%) had a family history of malignancies. Of these 8 patients, 7 (87.5%) were in group B (p=0.03) and 3 (37.5%) showed the same pathological type of neoplasm as their relatives. All GIST were positive for CD117 whereas associated malignancies were negative for this marker. CONCLUSION: We did not find immunohistochemical positivity for CD117 in malignancies associated with GIST. Given the special characteristics of the study population, the association between GIST and associated malignancies may be incidental.