RESUMEN
Five-year overall survival of stage III colorectal cancer (CRC) patients treated with standard adjuvant chemotherapy (ACHT) is highly variable. Genomic biomarkers and/or transcriptomic profiles identified lack of adequate validation. Aim of our study was to identify and validate molecular biomarkers predictive of ACHT response in stage III CRC patients by a transcriptomic approach. From a series of CRC patients who received ACHT, two stage III extreme cohorts (unfavorable vs. favorable prognosis) were selected. RNA-sequencing was performed from fresh frozen explants. Tumors were characterized for somatic mutations. Validation was performed in stage III CRC patients extracted from two GEO datasets. According to disease-free survival (DFS), 108 differentially expressed genes (104/4 up/downregulated in the unfavorable prognosis group) were identified. Among 104 upregulated genes, 42 belonged to olfactory signaling pathways, 62 were classified as pseudogenes (n = 17), uncharacterized noncoding RNA (n = 10), immune response genes (n = 4), microRNA (n = 1), cancer-related genes (n = 14) and cancer-unrelated genes (n = 16). Three out of four down-regulated genes were cancer-related. Mutational status (i.e., RAS, BRAF, PIK3CA) did not differ among the cohorts. In the validation cohort, multivariate analysis showed high PNN and KCNQ1OT1 expression predictive of shorter DFS in ACHT treated patients (p = 0.018 and p = 0.014, respectively); no difference was observed in untreated patients. This is the first study that identifies by a transcriptomic approach and validates PNN and KCNQ1OT1 as molecular biomarkers predictive of chemotherapy response in stage III CRC patients. After a further validation in an independent cohort, PNN and KCNQ1OT1 evaluation could be proposed to prospectively identify stage III CRC patients benefiting from ACHT.
Asunto(s)
Biomarcadores de Tumor/genética , Moléculas de Adhesión Celular/genética , Neoplasias Colorrectales/genética , Proteínas Nucleares/genética , Anciano , Quimioterapia Adyuvante/métodos , Fosfatidilinositol 3-Quinasa Clase I/genética , Estudios de Cohortes , Neoplasias Colorrectales/patología , Supervivencia sin Enfermedad , Regulación hacia Abajo/genética , Femenino , Perfilación de la Expresión Génica/métodos , Humanos , Masculino , Persona de Mediana Edad , Mutación/genética , Estadificación de Neoplasias/métodos , Canales de Potasio con Entrada de Voltaje/genética , Pronóstico , Análisis de Secuencia de ARN/métodos , Transducción de Señal/genética , Transcriptoma/genética , Regulación hacia Arriba/genéticaRESUMEN
PURPOSE: Uterine leiomyosarcomas are rare tumors characterized by their resistance to chemotherapy and radiation treatment. Surgery is the primary method of treatment, but for patients with unresectable disease, alternate therapeutic options are clearly warranted. According to initial observations of c-KIT expression, correlation with a bad prognosis, and the successful therapeutic possibility of STI571 in gastrointestinal stromal tumors, the data have encouraged us to study c-KIT expression in these tumors. EXPERIMENTAL DESIGN: We analyzed the expression of c-KIT and genetic assessment of exon 11 of c-kit gene in 32 uterine leiomyosarcomas. RESULTS: In 17 cases (53.1%), we observed a c-KIT expression in tumor cells. Of the 17 patients with distinct c-KIT-positive immunoreactivity, eight had I or II stage disease and nine had III or IV stage disease. Molecular genetic analysis of exon 11, analyzed by direct DNA sequencing, was performed for all of the c-KIT-positive uterine leiomyosarcomas. No mutations were found. CONCLUSION: The conventional chemotherapy in leiomyosarcomas appears to be ineffective for patients with metastatic or unresectable disease, and the management of these patients poses a special problem. In these women, new therapeutic strategies are warranted. The treatment with STI571 in leiomyosarcoma patients might be hypothesized, because uterine leiomyosarcomas also express c-KIT.