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Abstract Background The epidermal growth factor receptor (EGFR) is over-expressed in 70–75% of colorectal adenocarcinomas (CRC). The anti-EGFR monoclonal antibody cetuximab has been approved for the treatment of metastatic CRC, however tumor response to cetuximab has not been found to be associated with EGFR over-expression by immunohistochemistry (IHC). The aim of this study was to explore EGFR and the downstream effector phosphatase and tensin homologue deleted on chromosome 10 (PTEN) as potential predictors of response to cetuximab. Methods CRC patients treated with cetuximab by the Hellenic Cooperative Oncology group, whose formalin-fixed paraffin-embedded tumor tissue was available, were included. Tissue was tested for EGFR and PTEN by IHC and fluorescence in situ hybridization (FISH). Results Eighty-eight patients were identified and 72 were included based on the availability of tissue blocks with adequate material for analysis on them. All patients, except one, received cetuximab in combination with chemotherapy. Median follow-up was 53 months from diagnosis and 17 months from cetuximab initiation. At the time of the analysis 53% of the patients had died. Best response was complete response in one and partial response in 23 patients. In 16 patients disease stabilized. Lack of PTEN gene amplification was associated with more responses to cetuximab and longer time to progression (p = 0.042). Conclusion PTEN could be one of the molecular determinants of cetuximab response. Due to the heterogeneity of the population and the retrospective nature of the study, our results are hypothesis generating and should be approached with caution. Further prospective studies are needed to validate this finding.

Background: Thymomas are the most common tumor arising in the anterior mediastinum. Surgery is the cornerstone for the management of these tumors. The role of postoperative radiotherapy in Masaoka stage II thymomas remains controversial, but it is well established in the advanced stages. The aim of this study was to investigate the role of postoperative radiotherapy in the overall management of thymomas, and the evaluation of potential prognostic factors., Patients and Methods: Between 1989 and 2007, 41 thymoma patients underwent surgery and 27 of them received radiotherapy with a curative intent. The Masaoka staging system was used. The histopathological records and specimens of patients were thoroughly reviewed. Clinical and radiological evaluations took place every 6 months. The mean patient follow-up was 69 months (range: 2-212)., Results: DFS (disease free survival), TS (total survival) and DSS (disease specific survival) differed significantly between stages and histological types (p<0.04). Stage I patients were managed only surgically, with none recurring or dying. Concerning stage II patients, TS was significantly longer in non-irradiated cases (10/21) (p=0.025). Stage III (n=8) and IV (n=8) patients underwent postoperative radiotherapy, with 4/8 of stage IV disease also receiving induction chemotherapy. Six out of 8 stage III-IV patients recurred (1 distant and 5 intrathoracic failure), out of whom 4 died due to disease progression despite further treatment (all type C histology). The mean DFS and TS for stage III patients were 49.2 and 50.3 months respectively, with the corresponding values for stage IV being 14.5 and 29.1 months. Patients with myasthenia had a favorable outcome and the ones with complete resection a significantly longer DFS (p=0.0003) and DSS (p=0.039). The Cox regression analysis showed that myasthenia and tumor size are important prognostic factors for DFS (p<0.05)., Conclusion: Myasthenic patients have a more favorable prognosis. Radiotherapy can be omitted in totally resected stage I-II patients, whereas it is beneficial in more advanced stages.