Thymidylate synthase gene amplification predicts pemetrexed resistance in patients with advanced non-small cell lung cancer.

BACKGROUND: Thymidylate synthase (TYMS) expression in lung cancer tissue affects the therapeutic efficacy of pemetrexed (PMT). TYMS protein expression is primarily assessed using immunohistochemistry (IHC), but this method is not suitable for accurate quantitative analysis. It is not known whether the analysis of TYMS gene copy number using fluorescence in situ hybridization (FISH) is a useful method for assessment of TYMS expression. PATIENTS AND METHODS: The participants were patients with chemo-naïve advanced NSCLC treated with PMT plus carboplatin (CBDCA) in prospective clinical phase II study. TYMS expression was evaluated in 40 patients by gene copy number and protein expression using FISH and IHC. Therapeutic efficacy was evaluated by investigating the response rate (RR), disease control rate (DCR), progression-free survival (PFS), and overall survival (OS). RESULTS: TYMS gene amplification was detected in 8 patients (32 %) among 25 patients who could be evaluated for TYMS gene copy number. There were no patients with complete or partial response in the TYMS amplified group. RR and DCR were lower in the TYMS amplified group compared with the TYMS unamplified group (0 versus 35.3 %, p = 0.0539, 62.5 versus 94.1 %, p = 0.0443). PFS and OS were reduced in the TYMS amplified group. The analysis of TYMS gene copy number had higher sensitivity and specificity compared with TYMS protein expression (76.2 versus 50.0 %, 75.0 versus 66.7 %). CONCLUSION: The analysis of TYMS gene copy number is more suitable than TYMS protein expression for assessment of TYMS expression. TYMS gene amplification predicts outcome of patients receiving PMT with advanced NSCLC.

Role of Tamm-Horsfall protein and uromodulin in calcium oxalate crystallization.

One of the defenses against nephrolithiasis is provided by macromolecules that modulate the nucleation, growth, aggregation and retention of crystals in the kidneys. The aim of the present study was to determine the behavior of two of these proteins, Tamm-Horsfall and uromodulin, in calcium oxalate crystallization in vitro. We studied a group of 10 male stone formers who had formed at least one kidney stone composed of calcium oxalate. They were classified as having idiopathic nephrolithiasis and had no well-known metabolic risk factors involved in kidney stone pathogenesis. Ten normal men were used as controls, as was a group consisting of five normal women and another consisting of five pregnant women. Crystallization was induced by a fixed supersaturation of calcium oxalate and measured with a Coulter Counter. All findings were confirmed by light and scanning electron microscopy. The number of particulate material deposited from patients with Tamm-Horsfall protein was higher than that of the controls (P<0.001). However, Tamm-Horsfall protein decreased the particle diameter of the stone formers when analyzed by the mode of the volume distribution curve (P<0.002) (5.64 +/- 0.55 microm compared to 11.41 +/- 0.48 microm of uromodulin; 15.94 +/- 3.93 microm and 12.45 +/- 0.97 microm of normal men Tamm-Horsfall protein and uromodulin, respectively; 8.17 +/- 1.57 microm and 9.82 +/- 0.95 microm of normal women Tamm-Horsfall protein and uromodulin, respectively; 12.17 +/- 1.41 m and 12.99 +/- 0.51 microm of pregnant Tamm-Horsfall protein and uromodulin, respectively). Uromodulin produced fewer particles than Tamm-Horsfall protein in all groups. Nonetheless, the total volume of the crystals produced by uromodulin was higher than that produced by Tamm-Horsfall protein. Our results indicate a different effect of Tamm-Horsfall protein and uromodulin. This dual behavior suggests different functions. Tamm-Horsfall protein may act on nucleation and inhibit crystal aggregation, while uromodulin may promote aggregation of calcium oxalate crystals.

Role of Tamm-Horsfall protein and uromodulin in calcium oxalate crystallization

One of the defenses against nephrolithiasis is provided by macromolecules that modulate the nucleation, growth, aggregation and retention of crystals in the kidneys. The aim of the present study was to determine the behavior of two of these proteins, Tamm-Horsfall and uromodulin, in calcium oxalate crystallization in vitro. We studied a group of 10 male stone formers who had formed at least one kidney stone composed of calcium oxalate. They were classified as having idiopathic nephrolithiasis and had no well-known metabolic risk factors involved in kidney stone pathogenesis. Ten normal men were used as controls, as was a group consisting of five normal women and another consisting of five pregnant women. Crystallization was induced by a fixed supersaturation of calcium oxalate and measured with a Coulter Counter. All findings were confirmed by light and scanning electron microscopy. The number of particulate material deposited from patients with Tamm-Horsfall protein was higher than that of the controls (P<0.001). However, Tamm-Horsfall protein decreased the particle diameter of the stone formers when analyzed by the mode of the volume distribution curve (P<0.002) (5.64 ± 0.55 æm compared to 11.41 ± 0.48 æm of uromodulin; 15.94 ± 3.93 æm and 12.45 ± 0.97 æm of normal men Tamm-Horsfall protein and uromodulin, respectively; 8.17 ± 1.57 æm and 9.82 ± 0.95 æm of normal women Tamm-Horsfall protein and uromodulin, respectively; 12.17 ± 1.41 æm and 12.99 ± 0.51 æm of pregnant Tamm-Horsfall protein and uromodulin, respectively). Uromodulin produced fewer particles than Tamm-Horsfall protein in all groups. Nonetheless, the total volume of the crystals produced by uromodulin was higher than that produced by Tamm-Horsfall protein. Our results indicate a different effect of Tamm-Horsfall protein and uromodulin. This dual behavior suggests different functions. Tamm-Horsfall protein may act on nucleation and inhibit crystal aggregation, while uromodulin may promote aggregation of calcium oxalate crystals