Relationship of thymidylate synthase levels to outcome of malignant pleural mesothelioma patients treated with pemetrexed-based chemotherapy

7508

Background: Pemetrexed has shown activity in malignant pleural mesothelioma (MPM) but scanty data are available on the expression of thymidylate synthase (TS), its most important molecular target. Methods: From a database of 75 non-surgical, chemotherapy-naive MPM patients from our Institution in the period 2004–2008, 50 (male/female: 37/13, median age: 65 years) met the selection criteria i.e. epithelial type, availability of thoracoscopic tissue and outcome data. Pemetrexed was administered as single agent (14/50) or in combination with cisplatin or carboplatin (36/50). Retrospectively TS protein expression levels were evaluated by immunohistochemistry and quantified with H-score method. In addition, mRNA extraction was performed in 23 micro-dissected tissues and TS relative levels quantified by RT-PCR. Survival probability was assessed by Kaplan-Meier method and results compared by log-rank test. Cox multivariate analysis for survival was performed adjusting for clinical-pathological variables. Results: Thirty-two patients had progressive disease and 24 had died at the time of the analysis. Median time to progression (TTP) and median survival time (MST) were 11.6 and 20.9 months, respectively. Median TS H-score value was 90 (5–240). No correlation were found with sex, age, PS, stage and chemotherapy regimen. Patients with high TS H-score (4th quartile) had a significantly shorter MST (13.3 vs 21.1 months, p<0.01) and showed a trend for shorter TTP (8.3 vs 11.9 months, p=0.07). Median TS mRNA level was 1.88 (1–3.7 unit-less ratio) and a significant correlation between mRNA and protein expression (RS=0.67, p<0.0001) was found. Patients with high TS mRNA levels (4th quartile) had significantly shorter TTP (8.7 vs 14.7 months, p=0.019) and MST (11.7 vs 24.7, p=0.018). Multivariate analysis for survival indicated that TS protein levels were an independent prognostic factor (HR=2.17; CI 1.04–4.54; p=0.038). Conclusions: TS (protein and mRNA) levels predict outcome of epithelial MPM patients treated with pemetrexed-based chemotherapy. TS quantification, if confirmed in larger prospective studies, could be used to select those patients more likely to respond to chemotherapy.

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Bone sialoprotein is predictive of bone metastases in resectable non-small cell lung cancer: A case-control study and prevalence data

7049

Background: Bone metastases (BM) in non small cell lung cancer (NSCLC) may be present at diagnosis or develop in the follow up, are associated with a worse prognosis, and currently there are no chemical or biological markers predicting their clinical onset. Methods: Thirty cases of resected NSCLC which subsequently develop BM (group A - mean follow up time 27.2 months) were matched for several clinico-pathological parameters (including age, sex, stage of the disease, histology, differentiation grade, adjuvant therapy) to 30 cases of resected NSCLC without any metastases (group B - mean follow up time 75.1 months) and 26 resected NSCLC with non-bone metastatic (group C - mean follow up 21.1 months). Primary tumor samples were investigated by immunohistochemistry for 10 markers previously recognized to be involved in bone resorption or metastatization process (cathepsin K, bone sialoprotein [BSP], VEGF, MMP-2, p53, RECK, TIMP-1, CD-117, Ki-67 and TRAcP). For statistical analysis the intensity of the staining was assessed by a semi-quantitative score (0, <10%, 10–50%, >50% +ve tumor cells). Differences among groups were estimated by X-square test, whereas the prognostic impact of clinico-pathological parameters and markers expression was evaluated by univariate and multivariate analyses. Results: Among the different markers investigated, BSP was strongly associated to bone dissemination (p < 0.001) and, independently, to poor outcome (p = 0.02 by Mantel-Cox test). None of the other markers was differentially expressed within the groups or demonstrated a prognostic impact, both in terms of overall survival and of time interval to metastases. Based on these findings, the prevalence of BSP in NSCLC was further estimated in a large series of 120 resected lung carcinomas (M:F ratio 3:1; mean age 67 years; adenocarcinomas 55%, squamous cell carcinoma 39%, others 6%; stages: I 54%, II 17%, III 29%). BSP prevalence reached 40%, without any statistically significant difference according to histotype or other clinico-pathological parameters. Conclusions: BSP protein expression in resected NSCLC strongly predicts bone dissemination, and may therefore be useful in selecting patients for treatments targeted to inhibit bone metastatic spread.

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TGFalfa, EGFR and p70S6K expression in aggressive colorectal cancer (CRC)

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Background: Autocrine TGFa in CRC cells regulates cell adhesion via p70S6K phosphorylation in in vitro studies. The aim was to evaluate whether TGFa expression might be correlated with a higher metastatic behavior in vivo. Methods: 101 primitive CRC tumor samples with paraffin blocks available were retrospectively collected. All the specimens were immunohistochemically evaluated for EGFR clone 2–18C9 (Dako), and TGFa clone 213–4 (Calciochem) expression. A score of 0 to 3 was assigned according to staining intensity and extension. EGFR was also evaluated in randomly selected specimens with clone 111.6 (Neomarks) in 81 cases and clone 31G7 (Zymed) in 28 cases. Selected samples were stained for downstream signalling molecules STAT, p-akt, p-MAP kinase, mTor, p-mTor and p70S6K. Patients were divided into 2 groups according to tumor stage at diagnosis: group A stage II-III (51 pts); group B stage IV (50 pts). Results: EGFR clone 2–18C9 reacted in 68/101 (67.3%) cases. Positivity rates and correlation coefficients were: clone 111.6 42/81 (51.9%), r=0.54 (p<0.01); clone 31G7 20/28 (71.4%), r=0.76 (p<0.0001). TGFa was expressed in 79/101 (78.2%) cases. EGFR and TGFa diffuse staining (score 2, 3) was recorded in 14/51 (27.5%) and 18/51 (35.3%) patients in group A, and 26/50 (52.0%) and 27/50 (54.0%) in group B (p=0.01 and p=0.06). EGFR and TGFa coexpression was evident in 23/51 (45.1%) in group A and in 34/50 (68.0%) in group B (p=0.02). No difference in downstream signaling molecule expression was evident between the 2 groups. A positive correlation trend was recorded for p70S6K which was expressed in 8/20 (40%) and in 8/12 (66.7%) samples of group A and B (p=0.15). Conclusions: EGFR, TGFa and p70S6K expression was more common in patients with advanced stage at diagnosis confirming in vitro data. EGFR scores obtained with commercial antibodies from Zymed and Dako had a significant correlation.

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