Molecular profiling of isolated histological components of Wilms tumor implicates a commom role for the Wnt signaling pathway in kidney and tumor development

Wilms tumor (WT), a tumor composed of three histological components - blastema (BL), epithelia and stroma - is considered an appropriate model system to study the biological relationship between differentiation and tumorigenesis. To investigate molecular associations between nephrogenesis and WT, the gene expression pattern of individual cellular components was analyzed, using a customized platform containing 4,608 genes. WT gene expression patterns were compared to genes regulated during kidney differentiation. BL had a closer gene expression pattern to the earliest stage of normal renal development. The BL gene expression pattern was compared to that of fetal kidney (FK) and also between FK and mature kidney, identifying 25 common deregulated genes supposedly involved in the earliest events of WT onset. Quantitative RT-PCR was performed, confirming the difference in expression levels for 13 of 16 genes (81.2%) in the initial set and 8 of 13 (61.5%) in an independent set of samples. An overrepresentation of genes belonging to the Wnt signaling pathway was identified, namely PLCG2, ROCK2 and adenomatous polyposis coli (APC). Activation of the Wnt pathway was confirmed in WT, using APC at protein level and PLCG2 at mRNA and protein level. APC showed positive nuclear immunostaining for an independent set of WT samples, similarly to the FK in week 11. Lack of PLCG2 expression was confirmed in WT and in FK until week 18. Taken together, these results provided molecular evidence of the recapitulation of the embryonic kidney by WT as well as involvement of the Wnt pathway in the earliest events of WT onset.

Abdominal recurrence of osteogenic sarcoma: a case report

Nonpulmonary metastases from osteogenic sarcoma are rare. A patient had a localized osteogenic sarcoma of the left femur which recurred in the abdomen, a previously unreported metastatic site. An 18-year-old boy was treated for osteosarcoma. He had abdominal pain, vomiting, weight loss, and symptoms of intestinal obstruction at the time of relapse. The patient had diffuse widespread intraabdominal osteogenic sarcoma as the only site of initial recurrence. Abdominal computerized tomography revealed ascites and calcified masses on the hepatic and peritoneal surfaces. Laparoscopic visualization of the abdomen showed hemorrhagic ascites and multiple calcified tumor on the peritoneum, diaphragm, and liver. A biopsy of a representative lesion confirmed the diagnosis of osteogenic sarcoma. The patient died from progressive disease. As the initial treatment for patients with osteogenic sarcoma is intensified, the pattern of metastases may change. Unusual sites of recurrence such as in this patient may become more prevalent. A clinical presentation of an acute abdomen in a patient previously treated for osteogenic sarcoma should prompt suspicion of intraabdominal recurrence.