p53 missense but not truncation mutations are associated with low levels of p21(CIP1/WAF1) mRNA expression in primary human sarcomas

Primary proximal epithelioid sarcoma of the lung successfully treated with pneumonectomy and adjuvant chemotherapy

Primary sarcomas of the lung and proximal epithelial sarcomas (PESs) are extremely rare. Inactivation of INI1 has been found in the majority of epithelioid sarcoma (ES). We report the third known case of a primary PES of the lung along with immunohistochemical data. A 41-year-old man with HIV infection, on highly active antiretroviral therapy, presented with haemoptysis, shortness of breath and progressive weight loss for 2 months. He was eventually diagnosed with stage IIA cT2bN0M0 grade-2 primary PES of the lung. This patient underwent pneumonectomy and adjuvant chemotherapy with ifosfamide and doxorubicin. He remains in remission 36 months since diagnosis. Our case stands to help other clinicians as treatment of such rare cases is often reliant on case reports. We also posit a possible pathogenic mechanism given a history of HIV infection in this patient. The association of INI1 mutation with other atypical sarcomas in patients with HIV infection merits further evaluation.

Proximal-type epithelioid sarcoma in a 36-year-old man: closer immunoelectron-microscopic resemblance of the tumor cells to epithelial cells than to mesenchymal cells

Proximal-type epithelioid sarcoma (PES) is a rare neoplasm. We report a case of PES that arose in the perineal subcutis of a 36-year-old Japanese man who died within 4 months of the first clinical sign, probably due to massive pulmonary metastases. In the present study, we analyzed the tumor obtained at surgery, immunohistochemically, immunoelectron-microscopically and genetically. Although the tumor cells in the patient expressed both cytokeratin and vimentin immunohistochemically, they showed epithelial characteristics immunoelectron-microscopically because they had tonofilaments constructed of cytokeratin, not vimentin. In addition, the cytokeratins expressed on the tumor were glandular-type keratins. These findings indicate that PES may be a form of carcinoma in soft tissue. To ascertain the possible origin of the tumor, we compared the tumor immunohistochemically with fetal tissues. Although notochord and fetal peritoneal mesothelium were similar to the tumor antigenically, we could not confirm the specific origin of the tumor. Furthermore, the p53-WAF1 pathway did not contribute to tumorigenesis in the patient because the tumor had no mutation in exons 5-8 of the p53 gene and was immunohistochemically positive for WAF1.

Altered expression of G1 regulatory proteins in human soft tissue sarcomas

CONTEXT

Soft tissue sarcomas constitute a heterogeneous group of tumors for which tumorigenesis is not fully understood. Altered cell-cycle regulation may underlie the development and/or progression of human malignancies. However, data concerning the occurrence of cell-cycle aberrations in soft tissue sarcomas are very limited.

OBJECTIVES

To detect the abnormal features of cell-cycle regulatory proteins in soft tissue sarcomas and to determine the potential role of these proteins in clinical behavior.

DESIGN

The p53 and Rb-cyclin D pathways were investigated by immunohistochemical studies of p53, mdm2, pRb, p16, cyclin D1, and cdk4 proteins, respectively.

RESULTS

Of the 67 sarcomas analyzed, nuclear accumulation of p53 was detected in 25 samples (37%), and overexpression of mdm2 was found in 16 samples (24%). Both p53 and mdm2 expression correlated with tumor grade. Abnormalities involving the Rb-cyclin D pathway were identified in all of the tumors by the altered expression of either pRb (72%) or p16 (94%). Fourteen (21%) and 64 (96%) cases demonstrated cyclin D1 or cdk4 expression, respectively. Overexpression of cyclin D1 showed an association with pRb and p53. There was no correlation between pRb, p16, cyclin D1, or cdk4 and tumor grade or relapse.

CONCLUSION

Disturbance in the cell-cycle regulatory system involving the p53 pathway and the Rb-cyclin D pathway is relatively frequent in soft tissue sarcomas and may be a contributing factor in the tumorigenesis of these tumors. The alterations in the Rb-cyclin D pathway probably constitute an early event, whereas the abnormalities in the p53 pathway seem to be involved in tumor progression. It is noteworthy that cyclin D1 may play a key role in linking both pathways.