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Tumor specimens from patients in a trial of cisplatin-based adjuvant chemotherapy for non–small-cell lung cancer were analyzed for the presence of ERCC1, an enzyme that participates in the repair of DNA damage caused by cisplatin. The absence of ERCC1 in the tumor was associated with a survival benefit from cisplatin-based adjuvant chemotherapy, whereas patients whose tumor expressed the enzyme failed to benefit from the chemotherapy. The absence of ERCC1 in the tumor was associated with a survival benefit from cisplatin-based adjuvant chemotherapy, whereas patients whose tumor expressed the enzyme failed to benefit from the chemotherapy. Lung cancer is a leading cause of death from cancer in most industrialized countries. 1 Despite undergoing complete resection of non–small-cell lung cancer, 33% of patients with pathological stage IA die within 5 years, as do 77% of those with pathological stage IIIA. 2 Clinical trials have tested the ability of adjuvant chemotherapy to improve survival after complete resection of non–small-cell lung cancer. The International Adjuvant Lung Cancer Trial (IALT) demonstrated an absolute benefit of 4.1% in 5-year overall survival among 1867 patients who were treated with adjuvant cisplatin-based chemotherapy. 3 Several other randomized studies have confirmed the benefit of postoperative platinum-based therapy . . .

The phase III randomized trial, JCOG1113 has demonstrated the non-inferiority of gemcitabine and S-1 (GS) therapy to gemcitabine and cisplatin (GC) therapy for advanced biliary tract cancer (BTC). However, biomarkers for favorable therapy or to predict patient prognosis remain lacking. In this study, we evaluated five candidate biomarkers potentially involved in the efficacy of cisplatin or S-1 by immunostaining tumor specimens obtained from JCOG1113 participants. The participants were randomly divided into training or test sets and classified into high- or low-expression groups based on the cutoff value calculated from the immunostaining results for each biomarker in the training set. Associations between the expression of each biomarker and the outcomes in JCOG1113 were analyzed. Among the 148 eligible participants, no interaction was observed between the treatment arms of GC or GS for any factor or biomarker. However, high excision repair cross-complementing gene 1 (ERCC1) was associated with poor overall survival (HR, 2.226; 95% CI, 1.160–4.272) and progression-free survival (HR, 1.793; 95% CI, 0.945–3.402) compared with low ERCC1 in the training set. Similar trends were observed for the test set. Our results indicate that in advanced BTC, high ERCC1 expression is a poor prognostic factor.

Crossovers (COs) play a critical role in ensuring proper alignment and segregation of homologous chromosomes during meiosis. How the cell balances recombination between CO vs. noncrossover (NCO) outcomes is not completely understood. Further lacking is what constrains the extent of DNA repair such that multiple events do not arise from a single double-strand break (DSB). Here, by interpreting signatures that result from recombination genome-wide, we find that synaptonemal complex proteins promote crossing over in distinct ways. Our results suggest that Zip3 (RNF212) promotes biased cutting of the double Holliday-junction (dHJ) intermediate whereas surprisingly Msh4 does not. Moreover, detailed examination of conversion tracts in sgs1 and mms4-md mutants reveal distinct aberrant recombination events involving multiple chromatid invasions. In sgs1 mutants, these multiple invasions are generally multichromatid involving 3-4 chromatids; in mms4-md mutants the multiple invasions preferentially resolve into one or two chromatids. Our analysis suggests that Mus81/Mms4 (Eme1), rather than just being a minor resolvase for COs is crucial for both COs and NCOs in preventing chromosome entanglements by removing 3'- flaps to promote second-end capture. Together our results force a reevaluation of how key recombination enzymes collaborate to specify the outcome of meiotic DNA repair.

Background: The FAST was a factorial trial in first-line treatment of advanced non-small-cell lung cancer (NSCLC), addressing the role of replacing cisplatin with a non-platinum agent. The prognostic and predictive effect of ERCC1/BRCA1 expression and ERCC1/XPD/XRCC1–3 gene polymorphisms on outcomes of patients was examined. Methods: Patients were randomised to receive treatment with or without cisplatin. ERCC1/BRCA1 expression was determined by immunohistochemistry. ERCC1 ( C8092A , C118T ), XPD ( Lys751Gln ), XRCC1 ( Arg399Gln ) and XRCC3 ( Thr241Met ) gene polymorphisms were evaluated on tumour DNA by TaqMan allelic discrimination assay. Results: Tumour samples were available from 110 of 433 patients enrolled: 54.7% were ERCC1 positive and 51.4% were BRCA1 positive. Overall, ERCC1-negative patients had better response rate ( P =0.004), progression-free survival ( P =0.023) and overall survival ( P =0.012) compared with positive ones, with no statistically significant treatment interaction. The BRCA1-positive patients showed numerically better outcomes, although not statistically significant, with no treatment interaction. Among DNA repair gene polymorphisms, only XRCC1 Gln/Gln genotype evidenced a potential prognostic role ( P =0.036). Conclusion: This study confirms the prognostic role of ERCC1 expression and XRCC1 ( Arg399Gln ) polymorphism in advanced NSCLC treated with first-line chemotherapy. None of these biomarkers was shown to be a specific predictive factor of cisplatin efficacy.

Alternative lengthening of telomeres (ALT) in human cells is a conserved process that is often activated in telomerase-deficient human cancers. This process exploits components of the recombination machinery to extend telomere ends, thus allowing for increased proliferative potential. Human MUS81 (Mus81 in Saccharomyces cerevisiae) is the catalytic subunit of structure-selective endonucleases involved in recombination and has been implicated in the ALT mechanism. However, it is unclear whether MUS81 activity at the telomere is specific to ALT cells or if it is required for more general aspects of telomere stability. In this study, we use S. cerevisiae to evaluate the contribution of the conserved Mus81-Mms4 endonuclease in telomerase-deficient yeast cells that maintain their telomeres by mechanisms akin to human ALT. Similar to human cells, we find that yeast Mus81 readily localizes to telomeres and its activity is important for viability after initial loss of telomerase. Interestingly, our analysis reveals that yeast Mus81 is not required for the survival of cells undergoing recombination-mediated telomere lengthening, i.e. for ALT itself. Rather we infer from genetic analysis that Mus81-Mms4 facilitates telomere replication during times of telomere instability. Furthermore, combining mus81 mutants with mutants of a yeast telomere replication factor, Rrm3, reveals that the two proteins function in parallel to promote normal growth during times of telomere stress. Combined with previous reports, our data can be interpreted in a consistent model in which both yeast and human MUS81-dependent nucleases participate in the recovery of stalled replication forks within telomeric DNA. Furthermore, this process becomes crucial under conditions of additional replication stress, such as telomere replication in telomerase-deficient cells.

Yeast Rad1–Rad10 (XPF–ERCC1 in mammals) incises UV, oxidation, and cross-linking agent-induced DNA lesions, and contributes to multiple DNA repair pathways. To determine how Rad1–Rad10 catalyzes inter-strand crosslink repair (ICLR), we examined sensitivity to ICLs from yeast deleted for SAW1 and SLX4 , which encode proteins that interact physically with Rad1–Rad10 and bind stalled replication forks. Saw1, Slx1, and Slx4 are critical for replication-coupled ICLR in mus81 deficient cells. Two rad1 mutations that disrupt interactions between Rpa1 and Rad1–Rad10 selectively disable non-nucleotide excision repair (NER) function, but retain UV lesion repair. Mutations in the analogous region of XPF also compromised XPF interactions with Rpa1 and Slx4, and are proficient in NER but deficient in ICLR and direct repeat recombination. We propose that Rad1–Rad10 makes distinct contributions to ICLR depending on cell cycle phase: in G1, Rad1–Rad10 removes ICL via NER, whereas in S/G2, Rad1–Rad10 facilitates NER-independent replication-coupled ICLR. The yeast Rad1–Rad10 complex has multiple roles in DNA damage repair. Here the authors uncover mutants that uncouple the roles in UV excision repair and non-NER functions.

To ensure proper transmission of genetic information, cells need to preserve and faithfully replicate their genome, and failure to do so leads to genome instability, a hallmark of both cancer and aging. Defects in genes involved in guarding genome stability cause several human progeroid syndromes, and an age‐dependent accumulation of mutations has been observed in different organisms, from yeast to mammals. However, it is unclear whether the spontaneous mutation rate changes during aging and whether specific pathways are important for genome maintenance in old cells. We developed a high‐throughput replica‐pinning approach to screen for genes important to suppress the accumulation of spontaneous mutations during yeast replicative aging. We found 13 known mutation suppression genes, and 31 genes that had no previous link to spontaneous mutagenesis, and all acted independently of age. Importantly, we identified PEX19, encoding an evolutionarily conserved peroxisome biogenesis factor, as an age‐specific mutation suppression gene. While wild‐type and pex19Δ young cells have similar spontaneous mutation rates, aged cells lacking PEX19 display an elevated mutation rate. This finding suggests that functional peroxisomes may be important to preserve genome integrity specifically in old cells. We developed a high‐throughput approach to screen for genes important to suppress the accumulation of spontaneous mutations during yeast replicative aging. We found 13 known and 32 novel mutation suppression genes. Remarkably, one of these genes, PEX19, encoding an evolutionarily conserved peroxisome biogenesis factor, acts in an age‐dependent manner; while wild‐type and pex19Δ young cells have similar spontaneous mutation rates, aged cells lacking PEX19 display an elevated mutation rate.

Homologous recombination is an evolutionally conserved mechanism that promotes genome stability through the faithful repair of double-strand breaks and single-strand gaps in DNA, and the recovery of stalled or collapsed replication forks. Saccharomyces cerevisiae ATP-dependent DNA helicase Srs2 (a member of the highly conserved UvrD family of helicases) has multiple roles in regulating homologous recombination. A mutation (srs2K41A) resulting in a helicase-dead mutant of Srs2 was found to be lethal in diploid, but not in haploid, cells. In diploid cells, Srs2K41A caused the accumulation of inter-homolog joint molecule intermediates, increased the levels of spontaneous Rad52 foci, and induced gross chromosomal rearrangements. Srs2K41A lethality and accumulation of joint molecules were suppressed by inactivating Rad51 or deleting the Rad51-interaction domain of Srs2, whereas phosphorylation and sumoylation of Srs2 and its interaction with sumoylated proliferating cell nuclear antigen (PCNA) were not required for lethality. The structure-specific complex of crossover junction endonucleases Mus81 and Mms4 was also required for viability of diploid, but not haploid, SRS2 deletion mutants (srs2Δ), and diploid srs2Δ mus81Δ mutants accumulated joint molecule intermediates. Our data suggest that Srs2 and Mus81-Mms4 have critical roles in preventing the formation of (or in resolving) toxic inter-homolog joint molecules, which could otherwise interfere with chromosome segregation and lead to genetic instability.

BackgroundVaginal brachytherapy is currently recommended as adjuvant treatment in patients with high-intermediate risk endometrial cancer to maximize local control and has only mild side effects and no or limited impact on quality of life. However, there is still considerable overtreatment and also some undertreatment, which may be reduced by tailoring adjuvant treatment to the patients’ risk of recurrence based on molecular tumor characteristics.Primary objectivesTo compare the rates of vaginal recurrence in women with high-intermediate risk endometrial cancer, treated after surgery with molecular-integrated risk profile-based recommendations for either observation, vaginal brachytherapy or external pelvic beam radiotherapy or with standard adjuvant vaginal brachytherapyStudy hypothesisAdjuvant treatment based on a molecular-integrated risk profile provides similar local control and recurrence-free survival as current standard adjuvant brachytherapy in patients with high-intermediate risk endometrial cancer, while sparing many patients the morbidity of adjuvant treatment and reducing healthcare costs.Trial designA multicenter, international phase III randomized trial (2:1) of molecular-integrated risk profile-based adjuvant treatment (experimental arm) or adjuvant vaginal brachytherapy (standard arm).Major inclusion/exclusion criteriaWomen aged 18 years and over with a histological diagnosis of high-intermediate risk endometrioid endometrial cancer after total abdominal or laparoscopic hysterectomy and bilateral salpingo-oophorectomy. High-intermediate risk factors are defined as: (i) International Federation of Gynecology and Obstetrics stage IA (with invasion) and grade 3; (ii) stage IB grade 1 or 2 with age ≥60 and/or lymph-vascular space invasion; (iii) stage IB, grade 3 without lymph-vascular space invasion; or (iv) stage II (microscopic and grade 1).EndpointsThe primary endpoint is vaginal recurrence. Secondary endpoints are recurrence-free and overall survival; pelvic and distant recurrence; 5-year vaginal control (including treatment for relapse); adverse events and patient-reported symptoms and quality of life; and endometrial cancer-related healthcare costs.Sample size500 eligible and evaluable patients.Estimated dates for completing accrual and presenting resultsEstimated date for completing accrual will be late 2021. Estimated date for presentation of (first) results is expected in 2023.Trial registrationThe trial is registered at clinicaltrials.gov (NCT03469674) and ISRCTN (11659025).

Purpose The combination of docetaxel, cisplatin, and S-1 (DCS) chemotherapy is expected to be a promising regimen for advanced gastric cancer. This study was performed to evaluate the efficacy and safety of neoadjuvant DCS chemotherapy for locally advanced resectable gastric cancer. Methods Patients with locally advanced gastric cancer received 2 courses of preoperative chemotherapy with S-1 (40 mg/m 2 b.i.d.) on days 1–14 and docetaxel (60 mg/m 2 ) plus cisplatin (60 mg/m 2 ) on day 8 every 3 weeks, followed by standard curative surgery within 4–8 weeks. The primary endpoint was R0 resectability. Expression of damage DNA binding protein complex subunit 2 (DDB2)/excision repair cross-complementing 1 (ERCC1) in the pretreated tumor tissues was examined by immunohistochemistry. Results A total of 43 patients received neoadjuvant chemotherapy. The response rate was 74.4 %, and disease control ratio was 100 %. Grade 4 neutropenia developed in 53.5 % of patients and febrile neutropenia in 16.3 %. Non-hematological grade 3/4 adverse events were anorexia (23.3 %), nausea (14.0 %), and diarrhea (23.3 %), but these were generally transient and manageable. The proportion of R0 resections in the 43 eligible patients was 90.7 %, and a pathological response was found in 65.9 % of patients. There were no treatment-related deaths and no major surgical complications. The accuracy of the combination of DDB2 and ERCC1 expression for predicting chemoresistance was 82.5 %. Conclusions Preoperative treatment with DCS combination for locally advanced gastric cancer demonstrated a sufficient R0 resection rate and a good pathological response with manageable toxicities. The DDB2/ERCC1-high phenotype, as determined by immunohistochemistry, may be useful predictor of resistance to DCS chemotherapy.