Matsunaga T, Shirasawa H, Hishiki T, Yoshida H, Kouchi K, Ohtsuka Y, Kawamura K, Etoh T, Ohnuma N
Department of Pediatric Surgery, Chiba University, School of Medicine, Japan.
Clin Cancer Res. 2000 Aug;6(8):3199-204.
A substantial fraction of neuroblastomas found by mass screening have been suggested to regress spontaneously because of the high incidence of infantile neuroblastomas in the screening population. In this study, 70 neuroblastomas were analyzed for expression of proto-oncogenes related to neuronal differentiation to clarify the biological significance of proto-oncogene expression in the screening-positive and -negative tumors. The tumors consisted of 39 neuroblastomas found by screening (group 1), 16 non-N-myc-amplified neuroblastomas found by clinical symptom(s) (group 2), and 15 N-myc-amplified neuroblastomas found by clinical symptom(s) (group 3). The expression of c-src, trk A, and N-myc in tumor tissues was analyzed by quantitative RNA PCR. Neuronal c-srcN2 expression varied significantly in the following order: group 1 > group 2 > group 3. The level of expression of trk A was markedly reduced in group 3 but did not differ in groups 1 and 2. Most tumors in group 3 overexpressed N-myc. However, N-myc expression in group 1 was significantly higher than that in group 2. Thus, the characteristics of proto-oncogene expression in screening-positive tumors included enhanced expression of c-srcN2 and N-myc mRNA, regardless of nonamplification of N-myc. Our results suggest that the role of N-myc differs in neuroblastomas detected by screening and in N-myc-amplified tumors.
由于筛查人群中婴儿神经母细胞瘤的发病率较高，因此有人提出通过大规模筛查发现的相当一部分神经母细胞瘤会自发消退。在本研究中，对70例神经母细胞瘤进行分析，检测与神经元分化相关的原癌基因表达，以阐明原癌基因表达在筛查阳性和阴性肿瘤中的生物学意义。这些肿瘤包括通过筛查发现的39例神经母细胞瘤（第1组）、通过临床症状发现的16例非N - myc扩增神经母细胞瘤（第2组）和通过临床症状发现的15例N - myc扩增神经母细胞瘤（第3组）。通过定量RNA PCR分析肿瘤组织中c - src、trk A和N - myc的表达。神经元c - srcN2表达按以下顺序有显著差异：第1组>第2组>第3组。第3组中trk A的表达水平明显降低，但第1组和第2组之间没有差异。第3组中的大多数肿瘤过度表达N - myc。然而，第1组中N - myc的表达明显高于第2组。因此，筛查阳性肿瘤中原癌基因表达的特征包括c - srcN2和N - myc mRNA的表达增强，无论N - myc是否扩增。我们的结果表明，N - myc在筛查发现的神经母细胞瘤和N - myc扩增的肿瘤中的作用不同。
