Risk Factors for Relapse in Nonseminomatous Testicular Cancer After Postchemotherapy Retroperitoneal Lymph Node Dissection With Viable Residual Cancer.

PURPOSE: No consensus exists on the management of men with nonseminoma and viable nonteratomatous germ cell tumor in the postchemotherapy retroperitoneal lymph node dissection (pcRPLND) specimen after first-line chemotherapy. We analyzed surveillance versus different adjuvant chemotherapy regimens and the influence of time to pcRPLND on oncologic outcomes. METHODS: Data on 117 men treated with cisplatin-based first-line chemotherapy between 1990 and 2018 were collected from 13 institutions. All patients had viable nonteratomatous germ cell tumor in the pcRPLND specimen. Surgery was performed after a median of 57 days, followed by either surveillance (n = 64) or adjuvant chemotherapy (n = 53). Primary end points were progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS). RESULTS: After controlling for International Germ Cell Cancer Cooperative Group risk group and percent of viable malignant cells found at RPLND, no difference was observed between men managed with surveillance or adjuvant chemotherapy regarding PFS (hazard ratio [HR], 0.72 [95% CI, 0.32 to 1.6]; P = .4), CSS (HR, 0.69; 95% CI, 0.20 to 2.39; P = .6), and OS (HR, 0.78 [95% CI, 0.25 to 2.44]; P = .7). No statistically significant differences for PFS, CSS, or OS were observed on the basis of chemotherapy regimen or in men treated with pcRPLND ≤57 versus >57 days after first-line chemotherapy. Residual disease with <10% versus ≥10% viable cancer cells were associated with a longer PFS (HR, 3.22 [95% CI, 1.29 to 8]; P = .012). Relapse in the retroperitoneum was observed in 34 (29%) men. CONCLUSION: Men with a complete resection at pcRPLND and <10% viable cells have favorable outcomes without further treatment. Complete retroperitoneal resection seems more important than early pcRPLND.

Risk of residual cancer after complete response following first-line chemotherapy in men with metastatic non-seminomatous germ cell tumour and International Germ Cell Cancer Cooperative Group intermediate/poor prognosis: A multi-institutional retrospective cohort study.

INTRODUCTION: Current guidelines recommend surveillance in metastatic non-seminomatous germ cell tumour patients treated with first-line-chemotherapy and a complete clinical response (normalisation of serum tumour markers and residual masses <1 cm). However, this recommendation is based on a series including patients with good prognosis according to International Germ Cell Cancer Cooperative Group prognostic group (IGCCCG-PG). The aim of this study was to analyse the proportion of residual teratoma and survival among patients with intermediate/poor IGCCCG-PG and a complete clinical response after first-line-chemotherapy. MATERIAL & METHODS: This is a retrospective study of men with intermediate/poor IGCCCG-PG, who had a complete clinical response after first-line chemotherapy. Patients were either followed by surveillance or treated with post-chemotherapy retroperitoneal lymph node dissection (pcRPLND). RESULTS: Between 2009 and 2018, 143 men with intermediate (n = 83) or poor (n = 60) IGCCCG-PG were treated at 11 international centres. Among 33 patients treated with pcRPLND, the specimen showed teratoma and viable cancer in 16 (48%) and 4 (12%). During a median a 7-year follow-up, 20/110 (18%) patients managed with surveillance relapsed, of whom seven (6%) had a retroperitoneal-only relapse versus 2/33 patients managed with pcRPLND relapsed. No difference was observed regarding overall survival (OS) among men treated with pcRPLND or surveillance (5-year OS, 93% and 89%, p-value = 0.35). The median time-to-recurrence among men on surveillance was 1.3 years (range: 0.3-9.1), and the most common sites of relapses included retroperitoneum (11%), chest (5%), and bones (4%). CONCLUSIONS: While most men with intermediate/poor IGCCCG-PG harbour teratoma/cancer in the retroperitoneum despite a complete response to first-line-chemotherapy, only 6% managed with surveillance relapsed in the retroperitoneum. There was no significant difference in OS between the two groups.

PCR on yeast colonies: an improved method for glyco-engineered Saccharomyces cerevisiae.

BACKGROUND: Saccharomyces cerevisiae is extensively used in bio-industries. However, its genetic engineering to introduce new metabolism pathways can cause unexpected phenotypic alterations. For example, humanisation of the glycosylation pathways is a high priority pharmaceutical industry goal for production of therapeutic glycoproteins in yeast. Genomic modifications can lead to several described physiological changes: biomass yields decrease, temperature sensitivity or cell wall structure modifications. We have observed that deletion of several N-mannosyltransferases in Saccharomyces cerevisiae, results in strains that can no longer be analyzed by classical PCR on yeast colonies. FINDINGS: In order to validate our glyco-engineered Saccharomyces cerevisiae strains, we developed a new protocol to carry out PCR directly on genetically modified yeast colonies. A liquid culture phase, combined with the use of a Hot Start DNA polymerase, allows a 3-fold improvement of PCR efficiency. The results obtained are repeatable and independent of the targeted sequence; as such the protocol is well adapted for intensive screening applications. CONCLUSIONS: The developed protocol enables by-passing of many of the difficulties associated with PCR caused by phenotypic modifications brought about by humanisation of the glycosylation in yeast and allows rapid validation of glyco-engineered Saccharomyces cerevisiae cells. It has the potential to be extended to other yeast strains presenting cell wall structure modifications.

N-glycosylation humanization for production of therapeutic recombinant glycoproteins in Saccharomyces cerevisiae.

The production of therapeutic recombinant glycoproteins deals with three main issues: cost, production capacities, and glycosylation. Nowadays, such proteins are expressed in various complex expression systems (CHO, bacteria, etc.); the processes related to those production hosts are time consuming and expensive, or the question of posttranslational modifications (as glycosylation) control is still unresolved. There is a need to find an alternative approach, while maintaining high quality level: the new system must be able to add complex N-glycan structures to proteins of interest. Developed in several strains of Saccharomyces cerevisiae, GlycodExpress™ is an innovative technology that allows production of therapeutic recombinant glycoproteins with humanized and homogeneous N-glycan moieties. We show how to delete mannosyltransferases involved in host N-glycosylation to obtain more than 90% of homogeneity in glycan structures. The methodology developed to select the optimal fusion between a heterologous glycosyl-enzyme and a localization sequences is also presented. Finally, the screening of the best producing strain is illustrated.

The fucosyltransferase gene family: an amazing summary of the underlying mechanisms of gene evolution.

The fucosyltransferase gene family encodes enzymes that transfer fucose in alpha 1,2, alpha 1,3/4 and alpha 1,6 linkages on a large variety of glycans. The most ancient genes harbour a split coding sequence, and encode enzyme that transfer fucose at or near O- and N-peptidic sites (serine, threonine or chitobiose unit). Conversely, the more recent genes have a monoexonic coding sequence, and encode enzymes that transfer fucose at the glycan periphery. All basic mechanisms of gene evolution contribute to this amazing scenario: exon shuffling, transposition, point mutations, and duplication. As typical examples: (i) exon shuffling leads to the ancestral organization of the alpha 1,6 fucosyltransferase gene; (ii) the ancestor of alpha 1,2 fucosyltransferase genes is reshaped by retrotransposition at the same locus; (iii) duplication associated to point mutations leads to the most recent alpha 1,3/4 fucosyltransferase genes.