Unidad de Investigación Médica en Enfermedades Infecciosas, Hospital de Pediatría, Instituto Mexicano del Seguro Social, Centro Médico Nacional SXXI, Mexico, D.F., Mexico.
Unidad de Investigación Médica en Enfermedades Infecciosas, Hospital de Pediatría, Instituto Mexicano del Seguro Social, Centro Médico Nacional SXXI, Mexico, D.F., Mexico.
Arch Med Res. 2014 Feb;45(2):143-51. doi: 10.1016/j.arcmed.2013.12.009. Epub 2014 Jan 28.
Recurrent and specific chromosomal translocations have been described in four pediatric sarcomas belonging to the small round blue cell (SRBC) group of tumors. Identification of mRNA chimeras using RT-PCR discriminates among alveolar rhabdomyosarcoma (ARMS), Ewing's sarcoma (ES/pPNET), synovial sarcoma (SS) and desmoplastic small round cell tumor (DSRCT); however, frequencies of these translocations are variable. We present a retrospective study comparing histological examination and occurrence of major chromosomal translocations to validate the diagnosis and to assess the frequency of these molecular markers in a group of 92 small round blue cell (SRBC) tumor samples from Hospital Infantil de Mexico.
We tested a panel of RT-PCR assays to each RNA tumor sample from formalin-fixed, paraffin-embedded tumors to detect specific mRNA chimeras in 47 ES/pPNET, 19 ARMS, four SS, three DSRCT, and 19 other SRBC tumors.
After excluding poor RNA quality samples, we found translocations in 17/31 ES/pPNET (54.8%), 10/19 ARMS (52.6%), 4/4 SS (100%) and 4/4 DSRCT (100%). We found disagreement in only three samples: one ES/pPNET and one embryonal rhabdomyosarcoma harbor a PAX3-FOXO1 translocation (for ARMS), and one neuroepithelioma harboring a EWS-WT1 (for DSRCT). Unsuitable RNA was found in 20/92 samples (21.7%) and was related to necrosis, small amount of tumor tissue, and use of nitric acid in bone biopsies, but was not related to age of the block.
We found a significantly lower occurrence of chromosomal translocations in ES/pPNET compared to reports from other groups. Differences may exist in the frequencies of these molecular markers among different populations.
已在属于小圆蓝细胞（SRBC）肿瘤的 4 种儿科肉瘤中描述了复发性和特异性染色体易位。使用 RT-PCR 鉴定 mRNA 嵌合体可区分肺泡横纹肌肉瘤（ARMS）、尤因肉瘤（ES/pPNET）、滑膜肉瘤（SS）和促结缔组织增生性小圆细胞肿瘤（DSRCT）；然而，这些易位的频率是可变的。我们进行了一项回顾性研究，比较组织学检查和主要染色体易位的发生，以验证诊断，并评估这些分子标记在来自墨西哥儿童医院的 92 例小圆蓝细胞（SRBC）肿瘤样本中的频率。
我们测试了一组 RT-PCR 检测，以检测福尔马林固定、石蜡包埋肿瘤的每个 RNA 肿瘤样本中特定的 mRNA 嵌合体，用于检测 47 例 ES/pPNET、19 例 ARMS、4 例 SS、3 例 DSRCT 和 19 例其他 SRBC 肿瘤中的特定 mRNA 嵌合体。
在排除 RNA 质量差的样本后，我们发现 17/31 例 ES/pPNET（54.8%）、10/19 例 ARMS（52.6%）、4/4 例 SS（100%）和 4/4 例 DSRCT（100%）中存在易位。我们仅在 3 个样本中发现不一致：1 例 ES/pPNET 和 1 例胚胎性横纹肌肉瘤携带 PAX3-FOXO1 易位（用于 ARMS），1 例神经上皮瘤携带 EWS-WT1 易位（用于 DSRCT）。在 92 例样本中发现 20 例（21.7%）不适宜的 RNA，这与坏死、肿瘤组织量小以及在骨活检中使用硝酸有关，但与块的年龄无关。
与其他组的报告相比，我们发现 ES/pPNET 中染色体易位的发生率显著降低。这些分子标记在不同人群中的频率可能存在差异。
