The extracellular matrix (ECM) not only provides structural support in tissues but also regulates cellular processes and tissue homeostasis. The lysyl oxidase (LOX) family of enzymes, consisting of LOX and lysyl oxidase-like enzymes (LOXL1-4), is involved in ECM remodeling by catalyzing the crosslinking of collagen and elastin. Dysregulation of these enzymes is implicated in the pathogenesis of various diseases, including organ fibrosis and tumor development. Furthermore, LOX family members have been shown to affect radiotherapy responses, with specific involvement in radioresistance and radiation-induced fibrosis. This review summarizes the structural and functional characteristics of the LOX family, highlighting their roles in fibrotic diseases such as pulmonary fibrosis, liver fibrosis, and cardiac diseases, their roles in tumor progression, relevance in radiotherapy, and treatment targeting LOX and LOXLs. Understanding the underlying mechanisms and potential therapies is critical for developing novel strategies in both disease identification and management.

Abstract Breast fibrosis (BF) after radiotherapy remains one of the most dreaded late toxicities in breast cancer care, yet multiple additive predictors struggle to capture its underlying biological complexity. Radiation-induced lymphocyte apoptosis (RILA) has recently been associated with the risk of fibrosis more than 10 years post-RT. Here, we show that a combination of five independent factors, RILA, two SNPs in the CTGF and NBS1 genes, and two clinical variables (body-mass index and hypertension) exhibits several important interactions. Partition analysis identified six partly nested subgroups, which could be consolidated into three clinically meaningful risk groups. Machine-learning modelling verified and refined these groups, demonstrating a five-fold variation (17–83%) in BF risk with an AUC = 0.735 in ROC analysis using only these five features. Our study provides proof-of-concept that a biologically realistic subgroup-based approach sharpens predictive performance and may enable clinical identification of a subgroup of breast cancer patients highly susceptible to BF.

The sparing effect of FLASH irradiation with ultrahigh dose rates (UHDR), by applying high dose fractions in less than one second, on adverse reaction in many normal tissues but not on tumour control has the potential to widen the therapeutic window and advance cancer radiotherapy. However, the mechanism is poorly understood, preventing its optimal application in the clinic. Here we review the current knowledge of radiation-induced radicals and their reactions, including time factors which are rarely considered. Furthermore, experimental in vitro and in vivo data in the framework of prevailing hypotheses, and the role of low oxygen concentrations and reoxygenation, are discussed. Finally, potential protective mechanisms are considered based on such reactions and the role of oxygen. We argue that more than one mechanism may contribute to dose-rate dependent protection, and that differences exist between protective mechanisms in vitro and in vivo. Furthermore, we propose a new protective reaction linking radiation chemistry to the role of oxygen in FLASH irradiation and incorporating the differential responses of normal tissue and tumours.

Background:Prospectively collected long-term adverse event data with pre-radiotherapy assessment and regular follow-up reflecting 'real world settings' are still limited. Here, we present the available data on early and long-term outcomes up to eight years after radiotherapy in men with prostate cancer who participated in the international REQUITE cohort study, stratified by treatment modalities and patient characteristics. Methods:Longitudinal data on pre-radiotherapy, acute and late symptoms up to eight years after radiotherapy were available from 1760 non-metastatic prostate cancer patients recruited in seven European countries and the USA. External beam radiotherapy (EBRT) and/or brachytherapy were given with curative intent between 2014 and 2016 according to local regimens. Gastrointestinal (GI) and genitourinary (GU) symptoms including sexual dysfunction were prospectively assessed by healthcare professionals according to CTCAE v4.0. Patient-reported outcomes were collected. Results:The highest incidence of clinician-reported grade ≥ 2 long-term GI and GU symptoms were for proctitis (12.1%) and haematuria (12.9%) among the EBRT-only treated patients, and proctitis (6.4%) and urinary incontinence (32.4%) among the post-prostatectomy/EBRT patients. Incidence of grade 3 adverse events was below 1.5%, with the only exception of late urinary incontinence in post-prostatectomy patients (10.2%). Conclusion:The frequency and distribution of GI and GU symptoms in a real-world multicentre cohort of patients following prostate radiotherapy were comparable to those reported in large interventional trials. Our finding highlights the value of standardised data farming approaches like the REQUITE project. Most patients consented to provide their data for future cancer research which is available on request.

Rectal cancer is frequently diagnosed at a locally advanced stage and treated by neoadjuvant chemoradiation. Current efforts to improve treatment outcome are focused on intensifying neoadjuvant chemotherapy, which is associated with higher levels of toxicity. To discover alternative strategies, we establish patient-derived rectal cancer organoids that reflect clinical radiosensitivity and use these organoids to screen 1,596 drug-radiation combinations. We find that inhibitors of rat sarcoma virus/mitogen-activated protein kinase (RAS-MAPK) signaling, especially mitogen-activated protein kinase kinase (MEK) inhibitors, strongly enhance radiation response. Mechanistically, MEK inhibitors suppress radiation-induced activation of RAS-MAPK signaling and selectively downregulate RAD51, a component of the homologous recombination DNA repair pathway. Through testing drug-drug-radiation combinations in organoids and cell lines, we identify that a combined poly ADP-ribose polymerase (PARP) and MEK inhibition can further enhance radiosensitivity of colorectal cancers, which we confirm in mouse xenograft models. Our data support clinical testing of MEK and PARP combination therapy with radiation in locally advanced rectal cancers as an alternative to chemoradiation.

Locally advanced rectal cancer is usually treated by neoadjuvant chemoradiotherapy. However, tumor response rates to this treatment vary greatly. Thus, most patients do not reach a complete remission and have to undergo tumor resection. In the present study, we introduce a patient-derived rectal cancer organoid platform that reflects clinical radiosensitivity and use this to screen 1596 drug-radiation combinations. We identify inhibitors of RAS-MAPK signaling, especially MEK inhibitors, strongly synergizing with radiation response. Mechanistically, MEK inhibitors suppressed radiation-induced activation of RAS-MAPK signaling, and selectively downregulated the homologous recombination DNA repair pathway component RAD51, thereby achieving radio-enhancement. Through testing drug-drug-radiation combinations in organoids and cell lines, we identified synergism between PARP and MEK inhibitors to further enhance the effect of radiation. Our data support clinical testing of combined MEK and PARP inhibition with radiotherapy in locally advanced rectal cancers. ![Figure][1] ### Competing Interest Statement The authors have declared no competing interest. [1]: pending:yes

Background Ionotropic glutamate receptors α-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid receptor (AMPAR) and N-methyl-D-aspartate receptor (NMDAR) modulate proliferation, invasion and radioresistance in glioblastoma (GB). Pharmacological targeting is difficult as many in vitro-effective agents are not suitable for in patient applications. We aimed to develop a method to test the well tolerated AMPAR- and NMDAR-antagonist xenon gas as a radiosensitizer in GB. Methods We designed a diffusion-based system to perform the colony formation assay (CFA), the radiobiological gold standard, under xenon exposure. Stable and reproducible gas atmosphere was validated with oxygen and carbon dioxide as tracer gases. After checking for AMPAR and NMDAR expression via immunofluorescence staining we performed the CFA with the glioblastoma cell lines U87 and U251 as well as the non-glioblastoma derived cell line HeLa. Xenon was applied after irradiation and additionally tested in combination with NMDAR antagonist memantine. Results The gas exposure system proved compatible with the CFA and resulted in a stable atmosphere of 50% xenon. Indications for the presence of glutamate receptor subunits were present in glioblastoma-derived and HeLa cells. Significantly reduced clonogenic survival by xenon was shown in U87 and U251 at irradiation doses of 4–8 Gy and 2, 6 and 8 Gy, respectively ( p < 0.05). Clonogenic survival was further reduced by the addition of memantine, showing a significant effect at 2–8 Gy for both glioblastoma cell lines ( p < 0.05). Xenon did not significantly reduce the surviving fraction of HeLa cells until a radiation dose of 8 Gy. Conclusion The developed system allows for testing of gaseous agents with CFA. As a proof of concept, we have, for the first time, unveiled indications of radiosensitizing properties of xenon gas in glioblastoma.

Abstract Background Ionotropic glutamate receptors AMPAR and NMDAR modulate proliferation, invasion and radioresistance in glioblastoma (GB). Pharmacological targeting is difficult as many in vitro-effective agents are not suitable for in patient applications. We aimed to develop a method to test the well tolerated AMPAR- and NMDAR-antagonist xenon gas as radiosensitizer in GB. Methods We designed a diffusion-based system to perform the colony formation assay (CFA), the radiobiological gold standard, under xenon exposure. Stable and reproducible gas atmosphere was validated with oxygen and carbon dioxide as tracer gases. After checking for AMPAR and NMDAR expression via immunofluorescence staining we performed the CFA with the glioblastoma cell lines U87 and U251 as well as the non-glioblastoma derived cell line HeLa. Xenon was applied after irradiation and additionally tested in combination with NMDAR antagonist memantine. Results The gas exposure system proved compatible with the CFA and resulted in a stable atmosphere of 50% xenon. Glutamate receptor subunits were present in glioblastoma-derived and to a lesser extent in HeLa cells. Significant radiosensitization by xenon was shown in U251 and U87 at irradiation doses of 4–8 Gy and 2–8 Gy, respectively (p < .05). The effect was further enhanced by the addition of memantine, showing significant reduction in the surviving fraction already at 2 Gy for both glioblastoma cell lines (p < .05). Xenon did not increase the radiosensitivity of HeLa cells until a radiation dose of 8 Gy. Conclusion The developed system allows for testing of gaseous agents with CFA. As a proof of concept, we have, for the first time, unveiled radiosensitizing properties of xenon gas in glioblastoma.

OBJECTIVE:Most patients receive whole breast radiotherapy in a supine position. However, two randomised trials showed lower acute toxicity in prone position. Furthermore, in most patients, prone positioning reduced doses to the organs at risk. To confirm these findings, we compared toxicity outcomes, photographic assessment, and dosimetry between both positions using REQUITE data. METHODS:REQUITE is an international multi-centre prospective observational study that recruited 2069 breast cancer patients receiving radiotherapy. Data on toxicity, health-related quality of life (HRQoL), and dosimetry were collected, as well as a photographic assessment. A matched case control analysis compared patients treated prone (n = 268) versus supine (n = 493). Exact matching was performed for the use of intensity-modulated radiotherapy, boost, lymph node irradiation, chemotherapy and fractionation, and the nearest neighbour for breast volume. Primary endpoints were dermatitis at the end of radiotherapy, and atrophy and cosmetic outcome by photographic assessment at two years. RESULTS:At the last treatment fraction, there was no significant difference in dermatitis (p = .28) or any HRQoL domain, but prone positioning increased the risk of breast oedema (p < .001). At 2 years, patients treated in prone position had less atrophy (p = .01), and higher body image (p < .001), and social functioning (p < .001) scores. The photographic assessment showed no difference in cosmesis at 2 years (p = .22). In prone position, mean heart dose (MHD) was significantly lower for left-sided patients (1.29 Gy vs 2.10 Gy, p < .001) and ipsilateral mean lung dose (MLD) was significantly lower for all patients (2.77 Gy vs 5.89 Gy, p < .001). CONCLUSIONS:Prone radiotherapy showed lower MLD and MHD compared to supine position, although the risk of developing breast oedema during radiotherapy was higher. At 2 years the photographic assessment showed no difference in the cosmetic outcome, but less atrophy was seen in prone-treated patients and this seems to have a positive influence on the HRQoL domain of body image.

This manuscript presents the thought-provoking hypothesis that human life-time risk of cancer may be unexpectedly high because some defense mechanism (e.g. a tumour suppressor) has been lost during evolution. The authors base their argument on the much lower cancer risks in other long-lived species, including chimpanzees, and an evolutionary effect of dominant older males in small prehistoric tribes. Finally, they propose potential ways of testing their hypothesis. The manuscript refers to Pet’s paradox, i.e. that mammalian species have approximately similar cancer risks independent of their body size (and thus numbers of cells and cell divisions). However it goes beyond that in trying to explain why humans seem to have higher risks than similar species, e.g. chimpanzees. Overall the authors present their case in a clear manner. However, the manuscript would benefit from a discussion of the limitations in terms of uncertain or controversial aspects. Firstly, the evidence for the claim that the lifetime cancer risk in humans is higher than comparable species should be critically examined. Modern humans are under much more intense medical surveillance than even pets and other domesticated animals or animals kept in captivity. Thus detection and diagnosis of tumours is likely to be much more efficient in humans than in animals, perhaps with the exception of laboratory animals in cancer studies. Similarly, studies on wild animals such as whales examine only animals that were alive up until being found and do not include animals that have died and perished. Because of tumour growth dynamics, the time an animal is alive with a tumour may constitute only a short part of its lifespan. In addition, animal age is difficult to assess and it is known that cancer risk increases very strongly with time (to the power of six according to Peto (Phil Trans R Soc B 370:20150198, 2015; ref. #7). Is the age distribution known in the large studies on wild animals such as whales? Chimpanzees are not only somewhat smaller than humans but also have a markedly shorter lifespan, even in captivity. This needs to be taken into consideration when comparing species. Secondly, species with low risk of developing cancer may have developed

Background and purpose: Up to a quarter of breast cancer patients treated by surgery and radiotherapy experience clinically significant toxicity. If patients at high risk of adverse effects could be identified at diagnosis, their treatment could be tailored accordingly. This study was designed to identify common single nucleotide polymorphisms (SNPs) associated with toxicity two years following whole breast radiotherapy. Materials and Methods: A genome-wide association study (GWAS) was performed in 1,640 breast cancer patients with complete SNP, clinical, treatment and toxicity data, recruited across 18 European and US centres into the prospective REQUITE cohort study. Toxicity data (CTCAE v4.0) were collected at baseline, end of radiotherapy, and annual follow-up. A total of 7,097,340 SNPs were tested for association with the residuals of toxicity endpoints, adjusted for clinical, treatment co-variates and population substructure. Results: Quantile-quantile plots showed more associations with toxicity above the p 5 x 10-5 level than expected by chance. Eight SNPs reached genome-wide significance. Nipple retraction grade 2 was associated with the rs188287402 variant (p = 2.80 x 10-8), breastoedema grade > 2 with rs12657177 (p = 1. 12 x 10-10), rs75912034 (p = 1.12 x 10-10), rs145328458 (p = 1.06 x 10-9) and rs61966612 (p = 1.23 x 10- 9), induration grade > 2 with rs77311050 (p = 2.54 x 10-8) and rs34063419 (p = 1.21 x 10-8), and arm lymphoedema grade > 1 with rs643644 (p = 3.54 x 10-8). Heritability estimates across significant endpoints ranged from 25% to 39%. Our study did not replicate previously reported SNPs associated with breast radiation toxicity at the pre-specified significance level. Conclusions: This GWAS for long-term breast radiation toxicity provides further evidence for significant association of common SNPs with distinct toxicity endpoints. (c) 2023 The Authors. Published by Elsevier B.V. Radiotherapy and Oncology 187 (2023) 1-10 This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/).

Introduction Radiotherapy (RT) plays a central role in the neoadjuvant treatment of locally advanced rectal cancer. However, their intrinsic radioresistance is a major clinical challenge that limits the therapeutic efficacy. Therefore, the availability of radiosensitizers would improve the treatment of rectal cancers. Aberrant Ras-MAPK signaling is a hallmark of colorectal cancer (CRC). The impact of Ras-MAPK signaling on cellular response to RT in CRC and the therapeutic value of targeting the pathway to increase radiosensitivity is still unclear.