3'-UTR poly(T/U) tract deletions and altered expression of EWSR1 are a hallmark of mismatch repair-deficient cancers.

The genome-wide accumulation of DNA replication errors known as microsatellite instability (MSI) is the hallmark lesion of DNA mismatch repair (MMR)-deficient cancers. Although testing for MSI is widely used to guide clinical management, the contribution of MSI at distinct genic loci to the phenotype remains largely unexplored. Here, we report that a mononucleotide (T/U)16 tract located in the 3' untranslated region (3'-UTR) of the Ewing sarcoma breakpoint region 1 (EWSR1) gene is a novel MSI target locus that shows perfect sensitivity and specificity in detecting mismatch repair-deficient cancers in two independent populations. We further found a striking relocalization of the EWSR1 protein from nucleus to cytoplasm in MMR-deficient cancers and that the nonprotein-coding MSI target locus itself has a modulatory effect on EWSR1 gene expression through alternative 3' end processing of the EWSR1 gene. Our results point to a MSI target gene-specific effect in MMR-deficient cancers.

Intraoperative photodynamic therapy of the chest cavity in malignant pleural mesothelioma bearing rats.

BACKGROUND AND OBJECTIVE: Experimental assessment of anticancer effect, normal tissue damage, and toxicity of intrathoracic mTHPC-mediated photodynamic therapy (PDT) combined to surgery in malignant pleural mesothelioma (MPM) bearing rats. STUDY DESIGN/MATERIALS AND METHODS: Six days after implantation of syngenic malignant mesothelioma cells in the left chest cavity of Fischer rats (n = 21) and 4 days after sensitization (0.1 mg/kg mTHPC), a left-sided pneumonectomy was performed, followed by intraoperative light delivery (652 nm, fluence 20 J/cm(2)), either by spherical illumination of the chest cavity (fluence rate 15 mW/cm(2)) or by focal illumination of a tumor area (fluence rate 150 mW/cm(2)). Controls comprised tumor-bearing untreated animals, tumor-bearing animals undergoing pneumonectomy, and tumor-bearing animals undergoing pneumonectomy and light delivery without sensitization or sensitization without light delivery. No thoracocentesis was performed during follow-up. RESULTS: An invasively growing sarcomatous type of mesothelioma was found in all animals at day 10, without tumor necrosis in control animals. PDT resulted in 0.5-1 mm deep inhomogeneous tumor necrosis after spherical, and in a 1-2 mm deep tumor necrosis after focal illumination. No injury to mediastinal organs was observed, neither after PDT with spherical nor with focal light delivery except focal interstitial lung fibrosis at the mediastinal area of the opposite lung. All animals with pneumonectomy followed by spherical PDT of the entire tumor-bearing chest cavity died within 72 hours whereas all other animals survived. All animals that died presented massive pleural effusion. CONCLUSIONS: PDT following pneumonectomy in mesothelioma bearing rats was technically feasible and allowed to study its effect on tumor and normal tissues. PDT-related tumor necrosis was observed after spherical and focal light delivery, however, pneumonectomy followed by PDT with spherical light delivery to the tumor-bearing chest cavity resulted in fatal complications.

Prognosis of dermal lymphatic invasion with or without clinical signs of inflammatory breast cancer.

It is still an open debate whether tumor emboli in dermal lymphatics without inflammatory signs represent a similar bad prognosis like inflammatory breast cancer. We evaluated the prognostic role of dermal lymphatic invasion (DLI) in breast cancer with (DLI + ID) or without (DLI w/o ID) inflammatory disease (ID). From August 1988 to January 2000, 42 patients with DLI were irradiated. Twenty-five were classified as pT4, 13 out of them as pT4d (inflammatory disease); the 17 remaining patients had 1 T1c, 12 T2 and 4 T3 cancers with DLI. Axillary dissection revealed node-positive disease in 39/41 patients (median, 9 positive nodes). Thirty-eight out of 42 patients received adjuvant systemic treatment(s). After a mean follow-up of 33 months, 22/42 patients (52%) are disease-free. The actuarial 3-year disease-free survival is 50% (DLI w/o ID, 61%; DLI + ID, 31%; p < 0.03); the corresponding overall survival was 69% (DLI w/o ID, 87%; DLI + ID, 37%; p = 0.005). The presence or absence of ID was the only significant parameter for all endpoints in multivariate analyses. Dissemination occurred in 19 (45%), local relapse in 7 (n = 17%) and regional failure in 4 (10%). Nine patients (21%) had contralateral breast cancer/relapse. Despite the same histopathologic presentation, DLI w/o ID offered a significantly better disease-free survival and overall survival than ID. The finding of dermal lymphatic tumor invasion predicts a high probability for node-positive disease.