PTEN loss of expression predicts cetuximab efficacy in metastatic colorectal cancer patients

To evaluate whether the epidermal growth factor receptor (EGFR), K-Ras and PTEN, all members of the EGFR signalling pathway, may affect the clinical response in cetuximab-treated metastatic colorectal cancer (mCRC) patients. Twenty-seven cetuximab-treated mCRC patients were evaluated for drug response and investigated for EGFR protein expression and gene status, K-Ras mutational status and PTEN protein expression. Ten patients achieved a partial response (PR) to cetuximab-based therapy. All 27 patients showed EGFR protein overexpression. Epidermal growth factor receptor gene amplification was observed in eight out of 27 (30%) and chromosome 7 marked polysomy in 16 (59%) patients. Partial response was observed in six out of eight patients with EGFR gene amplification, four out of 16 with marked polysomy and none out of three with eusomy (P<0.05). The K-Ras wild-type sequence was observed in 17 patients, and nine of them experienced a PR. Conversely, K-Ras was mutated in 10 cases, of which one patient experienced a PR (P<0.05). The PTEN protein was normally expressed in 16 patients, and 10 of them achieved a PR. In contrast, no benefit was documented in 11 patients with loss of PTEN activity (P<0.001). Patients with EGFR gene amplification or chromosome 7 marked polysomy respond to cetuximab. In addition to K-Ras mutations, we demonstrate for the first time that the loss of PTEN protein expression is associated with nonresponsiveness to cetuximab.

Treatment outcomes with first and second line chemotherapy in advanced and metastatic pancreatic cancer patients

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Background: Recent advances in the treatment of pancreatic cancer might influence the management of locally advanced and metastatic disease, nonetheless prognosis remains dismal (1-year survival rates: 24%). The impact on survival of palliative second-line therapy is hotly debated. Methods: We retrospectively reviewed the clinical records of 103 pancreatic cancer patients admitted to San Camillo/Forlanini Hospital (Rome, Italy) and the Oncology Institute of Southern Switzerland during the period June, 1997 to August, 2005 [60 males, 43 females, median age 65 years (range 43–80); median ECOG performance status (PS): 1]. All patients received Gemcitabine as single agent (90%) or in combination with Oxaliplatin (10%) as upfront therapy. A total of 12 fluoropyrimidine-based salvage regimens were administered to 46 patients in the second line setting. Best supportive care was selected in 57 patients after failing first line therapy. Results: Of 103 evaluable patients, first line chemotherapy produced overall tumor growth control of partial response (PR) and stable disease(SD) by RECIST criteria of 52.4% with a median progression free survival (PFS) of 4.6 months. Multivariate analysis revealed that the most important prognostic factor for PFS was the patient’s PS, as patients with PS of 1–2 at diagnosis had significantly worse results than patients with PS = 0 (First line PFS: 110 days vs 193 days, p<0.05). Baseline CA19–9 and number of metastatic sites were not independent prognostic factors for better first-line PFS. PR was observed in 8/46 patients (17.3%) who received second line chemotherapy, SD in 10 (21.7%), and 28 patients progressed (61%). Median overall second line PFS was 3.2 months. Patients who had responded to first-line Gemcitabine were more likely to respond or attain stable disease with second-line treatment, with a PFS of 5.6 vs 2.85 months (p<0.05). The overall survival for all evaluable patients was 8.4 months. 1-year survival was 52% for patients treated with second line therapy. Conclusions: These results are consistent with historical studies and suggest that fluoropyrimidine-based salvage regimens have marginal but definite activity and should be considered in patients who have responded to first line chemotherapy with an optimal PS.

No significant financial relationships to disclose.