Detection of MYCN gene amplification in neuroblastic tumors by fluorescence in situ hybridization and its clinical significance

Abstract

Objective To explore the significance of MYCN gene amplification in children with neuroblastic tumors(NT). Methods The clinicopathological data of 154 cases with NT were reviewed, including general data, classification of pathology, clinical stage and prognosis.MYCN gene amplification was detected by fluorescence in situ hybridization(FISH) and its relationship between pathological characteristics and prognostic significance was analyzed. Results There was 154 cases of NT aged 1 day to 11 years, with a mean age of 26.1 months, and the median age of 20.5 months.Male and female ratio was 1.48∶1.00.According to International Neuroblastoma Staging System(INSS), 20 cases were of stageⅠ(13.0%), 23 cases of stageⅡ (14.9%), 43 cases of stage Ⅲ(27.9%), 64 cases of stage Ⅳ(41.6%) and 4 cases of Ⅳs (2.6%). There were 72 cases(46.8%) with favorable histology, and 82 cases(53.2%) with unfavorable histology.MYCN amplification was found in 20 cases (13.0%) and the signal ratio of MYCN and chromosome 2(CEP2) was 4.08-43.29.One hundred and thirty-four cases of MYCN non-amplification included MYCN gain in 91 cases(68.0%), MYCN negative in 43 cases(32.0%). MYCN expression showed the signi-ficant differences in ages, neuroblastoma type, international neuroblastoma pathology classification(INPC), mitosis kar-yorrhexis index (MKI), and clinical stages(all P 0.05). Of 20 MYCN amplification cases, 4 cases (20.0%) survived and 16 cases (80.0%) died, and the overall survival rate was 20.0%(4/20 cases), with survival time was (17.10±2.24) months; of 134 MYCN non-amplification cases, 96 cases (71.6%) survived and 38 cases (28.4%) died, with survival time of (28.71±1.28)months.Survival analysis showed the cases with MYCN amplification had worse prognosis(χ2=19.596, P<0.05). Conclusions Patients with MYCN amplification had poorer prognosis and lower incidence of MYCN amplification of pediatric NT was found in China. Key words: Neuroblastoma; MYCN gene; Fluorescence in situ hybridization; Child