Modified ypTNM Staging Classification for Gastric Cancer after Neoadjuvant Therapy: A Multi-Institutional Study.

BACKGROUND: The benefits of neoadjuvant therapy for patients with locally advanced gastric cancer (GC) are increasingly recognized. The 8th edition of the American Joint Committee on Cancer (AJCC) Staging Manual first proposed ypTNM staging, but its accuracy is controversial. This study aims to develop a modified ypTNM staging. PATIENTS AND METHODS: Clinicopathological data of 1,791 patients who underwent curative-intent gastrectomy after neoadjuvant therapy in the Surveillance, Epidemiology, and End Results database, as the development cohort, were retrospectively analyzed. Modified ypTNM staging was established based on overall survival (OS). We compared the prognostic performance of the AJCC 8th edition ypTNM staging and the modified staging for patients after neoadjuvant therapy. RESULTS: In the development cohort, the 5-year OS for AJCC stages I, II, and III was 58.8%, 39.1%, and 21.6%, respectively, compared with 69.9%, 54.4%, 34.4%, 24.1%, and 13.6% for modified ypTNM stages IA, IB, II, IIIA, and IIIB. The modified staging had better discriminatory ability (C-index: 0.620 vs. 0.589, p < .001), predictive homogeneity (likelihood ratio chi-square: 140.71 vs. 218.66, p < .001), predictive accuracy (mean difference in Bayesian information criterion: 64.94; net reclassification index: 35.54%; integrated discrimination improvement index: 0.032; all p < .001), and model stability (time-dependent receiver operating characteristics curves) over AJCC. Decision curve analysis showed that the modified staging achieved a better net benefit than AJCC. In external validation (n = 266), the modified ypTNM staging had superior prognostic predictive power (all p < .05). CONCLUSION: We have developed and validated a modified ypTNM staging through multicenter data that is superior to the AJCC 8th edition ypTNM staging, allowing more accurate assessment of the prognosis of patients with GC after neoadjuvant therapy. IMPLICATIONS FOR PRACTICE: The 8th edition of the American Joint Committee on Cancer (AJCC) Staging Manual first proposed ypTNM staging, but its accuracy is controversial. Based on multi-institutional data, this study developed a modified ypTNM staging, which is superior to the AJCC 8th edition ypTNM staging, allowing more accurate assessment of the prognosis of patients with gastric cancer after neoadjuvant therapy.

Effect of solute hydrogen bonding capacity on osmotic stability of lysosomes.

The effect of solute hydrogen bonding capacity on the osmotic stability of lysosomes was examined through measurement of free enzyme activity of lysosomes after their incubation in sucrose and poly(ethylene glycol) (PEG) (1500-6000 Da molecular mass) media. Free enzyme activity of the lysosomes was less in the PEG medium than that in the sucrose medium under the same hypotonic condition. The lysosomal enzyme latency loss decreased with increasing hydrogen bonding capacity of the solute. In addition, the lysosomes lost less latency at lower incubation temperature. The results indicate that solute hydrogen bonding capacity plays an important role in the osmotic protection of an incubation medium to lysosomes.

Loss of membrane cholesterol affects lysosomal osmotic stability.

Lysosomal destabilization is critical for the organelle and living cells. Using methyl-beta-cyclodextrin (M beta CD) to selectively deplete lysosomal membrane cholesterol, we investigated the effect of cholesterol on the organelle osmotic stability. The results show that loss of membrane cholesterol caused changes in the lysosomal osmotic properties. The lysosomes lost the ability to resist osmotic shock and became more sensitive to osmotic stress. As a result, the lysosomes lost membrane integrity rapidly. Microscope observation showed that the lysosomes were liable to swell in the hypotonic sucrose medium. It is presumably due to an enhancement of the lysosomal permeability to water caused by the loss of membrane cholesterol. The results indicate an important role of cholesterol in the maintenance of lysosomal stability.