Clinical significance of a highly sensitive analysis for gene dosage and the expression level of MYCN in neuroblastoma.

BACKGROUND: The amplification of the MYCN gene is one of the most powerful adverse prognosis factors in neuroblastoma, but the clinical significance of an enhanced expression of MYCN remains controversial. To reassess the clinical implications of MYCN amplification and expression in neuroblastoma, the status of amplification and the expression level of the MYCN gene of primary neuroblastoma samples were analyzed using highly sensitive analyses. METHODS: Using a quantitative polymerase chain reaction (PCR) method (TaqMan), the gene dosages (MYCN/p53) of 66 primary neuroblastoma samples were determined. In all 66 samples, the status of MYCN amplification has been determined previously by the Southern blotting method. Of the 54 samples with a single copy of MYCN based on the Southern blotting method, 23 samples were analyzed for MYCN amplification using the fluorescence in situ hybridization (FISH) method. The expression levels (MYCN/GAPDH) of 56 samples were determined by a quantitative reverse transcriptase (RT)-PCR method. RESULTS: Of the 54 samples with a single copy of MYCN based on the Southern blotting method, 46 samples showed MYCN gene dosages of less than 2.0, whereas the remaining 8 samples with dosages of more than 2.0 were tumors from patients with advanced-stage disease. The results of FISH supported the fact that these 8 samples contained a small number of MYCN-amplified cells. The cases of MYCN gene dosages of more than 2.0 were significantly associated with all other unfavorable prognostic factors (an age of >1 year at diagnosis [P <.0001], nonmass screening [P =.0003], advanced stage [P <.0001], diploid or tetraploid [P <.0001], and a Shimada unfavorable histology [P <.0001]). MYCN gene dosages of more than 2.0 were significantly associated with a high expression of MYCN (P =.0459). However, the expression level of MYCN was not significantly associated with any other prognostic factors. CONCLUSIONS: Quantitative PCR may thus be a useful modality for performing a highly sensitive and accurate assessment of the amplification and expression levels of the MYCN gene. In particular, the combination of the quantitative PCR system and the FISH method is considered to be a highly effective method for evaluating the status of MYCN amplification. In this highly sensitive analysis, MYCN amplification (MYCN/p53 > or = 2.0) was reconfirmed to be a strongly unfavorable factor, whereas the expression level of MYCN does not appear to be an independently significant prognosis factor.

Prenatally diagnosed cystic neuroblastoma: a report of two cases.

We report two cases of prenatally diagnosed cystic neuroblastoma (PDCN). In the first case, prenatal ultrasonography (US) at 33 weeks' gestation showed a 30 x 20 mm cyst at the upper pole of the right kidney. The size and content of the mass demonstrated no change during pregnancy. Postnatal US showed no change in the cystic mass 4 weeks after birth compared to the prenatal findings. The infant underwent total resection of the tumour at 28 days of age. In the second case, a left cystic mass measuring 50 x 40 mm was detected in a fetus in the 37th week of pregnancy. Postnatal US showed a cystic mass in the left adrenal gland. The US findings showed no change 18 days after birth and the infant underwent total resection of the tumour at 19 days of age. In both cases, pathological examination revealed a neuroblastoma and all of the biological prognostic factors were favourable. Surgical intervention was necessary for a final histological and biological diagnosis to be made. We recommend that prenatally suspected neuroblastomas should normally undergo surgical intervention, unless tumour size decreases within about 1 month after birth.

Hepatic foreign body - a sewing needle - in a child.

We report a case of a 1-year-old boy with a needle-like foreign body embedded in the liver. The foreign body was incidentally found in the right hypochondrium on routine chest X-ray during a periodic medical examination. He was asymptomatic and there was neither a history of swallowing a needle nor a puncture wound on his body. The results of blood tests and physical examination were entirely within normal limits. Computed tomography scan showed that the needle was completely buried in the liver. At laparotomy, some fibrous tissue and a scar were recognized between the surface of the left lobe of the liver and the parietal peritoneum of the upper abdominal wall. The end of the sewing needle was manually squeezed out and extracted from the liver. From this operative finding, it was assumed that the needle had penetrated the liver through his skin. His postoperative course was uneventful and he was discharged on postoperative day 8.

Adrenal cytomegaly: two cases detected by prenatal diagnosis.

We report our experience with two cases of adrenal cytomegaly, both of which were detected as cystic adrenal masses during prenatal ultrasonographic examinations. In Case 1, a left suprarenal cystic mass was detected in the fetus at 25 weeks of gestation. The mass, measuring 7 cm in diameter, did not show any change in size and was resected 26 days after birth. In Case 2, a right suprarenal lesion was found at 30 weeks of gestation. The cystic lesion, measuring 2 cm x 1.5 cm, did not change in size and was resected 3 months after birth. Adrenal cytomegaly is still not well known. It is characterized by the presence of large polyhedral cells with eosinophilic granular cytoplasm and enlarged nuclei in the adrenal cortex. This condition is thought to be a degenerative process but not a malignancy. Adrenal cytomegaly rarely forms cysts. It seemed to be impossible to diagnose preoperatively in our cases. Because of the difficulty of differentiating between cystic adrenal cytomegaly and other cystic diseases such as neuroblastoma, operative intervention is required in cases where the cysts do not decrease in size. Further study of a larger number of cases is needed to establish an optimal treatment protocol for these tumours.