Major pathologic response and RAD51 predict survival in lung cancer patients receiving neoadjuvant chemotherapy

RAD51 is a poor prognostic marker and a potential therapeutic target for oral squamous cell carcinoma

OBJECTIVES

RAD51 overexpression has been reported to serve as a marker of poor prognosis in several cancer types. This study aimed to survey the role of RAD51 in oral squamous cell carcinoma and whether RAD51 could be a potential therapeutic target.

MATERIALS AND METHODS

RAD51 protein expression, assessed by immunohistochemical staining, was used to examine associations with survival and clinicopathological profiles of patients with oral squamous cell carcinoma. Lentiviral infection was used to knock down or overexpress RAD51. The influence of RAD51 on the biological profile of oral cancer cells was evaluated. Cell viability and apoptosis after treatment with chemotherapeutic agents and irradiation were analyzed. Co-treatment with chemotherapeutic agents and B02, a RAD51 inhibitor, was used to examine additional cytotoxic effects.

RESULTS

Oral squamous cell carcinoma patients with higher RAD51 expression exhibited worse survival, especially those treated with adjuvant chemotherapy and radiotherapy. RAD51 overexpression promotes resistance to chemotherapy and radiotherapy in oral cancer cells in vitro. Higher tumorsphere formation ability was observed in RAD51 overexpressing oral cancer cells. However, the expression of oral cancer stem cell markers did not change in immunoblotting analysis. Co-treatment with RAD51 inhibitor B02 and cisplatin, compared with cisplatin alone, significantly enhanced cytotoxicity in oral cancer cells.

CONCLUSION

RAD51 is a poor prognostic marker for oral squamous cell carcinoma. High RAD51 protein expression associates with resistance to chemotherapy and radiotherapy. Addition of B02 significantly increased the cytotoxicity of cisplatin. These findings suggest that RAD51 protein may function as a treatment target for oral cancer.

TRIAL REGISTRATION

Number: KMUHIRB-E(I)-20190009 Kaohsiung Medical University Hospital, Kaohsiung, Taiwan, approved on 20190130, Retrospective registration.

Neoadjuvant immune checkpoint inhibitor therapy in resectable non-small cell lung cancer

Only a minority of lung cancers are resectable at diagnosis, and many of these will eventually relapse. Adjuvant chemotherapy in this setting has a modest survival advantage, and there is significant need for new approaches to improve cure rates. Checkpoint inhibitor immunotherapy has transformed the prognosis for advanced lung cancer, and is increasingly being used in the neoadjuvant setting alone, or in combination with cytotoxic chemotherapy. While this has demonstrated convincing improvements in event-free survival and pathologic response, questions remain over optimal duration of therapy, predictive and prognostic biomarkers, response assessment and combination with other modalities. In addition, these results must be considered in the context of recent positive studies of adjuvant immunotherapy. Here, we summarise preclinical context and clinical trials in this space, discuss areas of controversy and pitfalls, and consider future challenges.

Predictive signature of response to neoadjuvant chemotherapy in muscle-invasive bladder cancer integrating mRNA expression, taxonomic subtypes, and clinicopathological features

Background and objective

Neoadjuvant chemotherapy (NAC) followed by cystectomy is the standard of care in muscle-invasive bladder cancer (MIBC). Pathological response has been associated with longer survival, but no currently available clinicopathological variables can identify patients likely to respond, highlighting the need for predictive biomarkers. We sought to identify a predictive signature of response to NAC integrating clinical score, taxonomic subtype, and gene expression.

Material and methods

From 1994 to 2014, pre-treatment tumor samples were collected from MIBC patients (stage T2-4N0/+M0) at two Spanish hospitals. A clinical score was determined based on stage, hydronephrosis and histology. Taxonomic subtypes (BASQ, luminal, and mixed) were identified by immunohistochemistry. A custom set of 41 genes involved in DNA damage repair and immune response was analyzed in 84 patients with the NanoString nCounter platform. Genes related to pathological response were identified by LASSO penalized logistic regression. NAC consisted of cisplatin/methotrexate/vinblastine until 2000, after which most patients received cisplatin/gemcitabine. The capacity of the integrated signature to predict pathological response was assessed with AUC. Overall survival (OS) and disease-specific survival (DSS) were analyzed with the Kaplan-Meier method.

Results

LASSO selected eight genes to be included in the signature (RAD51, IFNγ, CHEK1, CXCL9, c-MET, KRT14, HERC2, FOXA1). The highest predictive accuracy was observed with the inclusion in the model of only three genes (RAD51, IFNɣ, CHEK1). The integrated clinical-taxonomic-gene expression signature including these three genes had a higher predictive ability (AUC=0.71) than only clinical score plus taxonomic subtype (AUC=0.58) or clinical score alone (AUC=0.56). This integrated signature was also significantly associated with OS (p=0.02) and DSS (p=0.02).

Conclusions

We have identified a predictive signature for response to NAC in MIBC patients that integrates the expression of three genes with clinicopathological characteristics and taxonomic subtypes. Prospective studies to validate these results are ongoing.

Pathological Response and Immune Biomarker Assessment in Non-Small-Cell Lung Carcinoma Receiving Neoadjuvant Immune Checkpoint Inhibitors

Simple Summary

Recently, the U.S. Food and Drug Administration (FDA) approved neoadjuvant immunotherapy plus chemotherapy for the treatment of resectable non-small-cell lung carcinoma (NSCLC) due to the clinical benefits reported in several clinical trials. In these settings, the pathological assessment of the tumor bed to quantify a pathological response has been used as a surrogate method of clinical benefit to neoadjuvant therapy. In addition, several clinical trials are including the assessment of tissue-, blood-, or host-based biomarkers to predict therapy response and to monitor the response to neoadjuvant treatment. In this manuscript, we provide an overview of current recommendations for the evaluation of pathological response and describe potential biomarkers used in clinical trials of neoadjuvant immunotherapy in resectable NSCLC.

Abstract

Lung cancer is the leading cause of cancer incidence and mortality worldwide. Adjuvant and neoadjuvant chemotherapy have been used in the perioperative setting of non-small-cell carcinoma (NSCLC); however, the five-year survival rate only improves by about 5%. Neoadjuvant treatment with immune checkpoint inhibitors (ICIs) has become significant due to improved survival in advanced NSCLC patients treated with immunotherapy agents. The assessment of pathology response has been proposed as a surrogate indicator of the benefits of neaodjuvant therapy. An outline of recommendations has been published by the International Association for the Study of Lung Cancer (IASLC) for the evaluation of pathologic response (PR). However, recent studies indicate that evaluations of immune-related changes are distinct in surgical resected samples from patients treated with immunotherapy. Several clinical trials of neoadjuvant immunotherapy in resectable NSCLC have included the study of biomarkers that can predict the response of therapy and monitor the response to treatment. In this review, we provide relevant information on the current recommendations of the assessment of pathological responses in surgical resected NSCLC tumors treated with neoadjuvant immunotherapy, and we describe current and potential biomarkers to predict the benefits of neoadjuvant immunotherapy in patients with resectable NSCLC.

Neoadjuvant Intratumoral Immunotherapy with TLR9 Activation and Anti-OX40 Antibody Eradicates Metastatic Cancer

The combination of the synthetic TLR9 ligand CpG and agnostic OX40 antibody can trigger systemic antitumor immune responses upon co-injection into the tumor microenvironment, eradicating simultaneous untreated sites of metastatic disease. Here we explore the application of this in situ immunotherapy to the neoadjuvant setting. Current neoadjuvant checkpoint blockade therapy is delivered systemically, resulting in off-target adverse effects. In contrast, intratumoral immunotherapy minimizes the potential for toxicities and allows for greater development of combination therapies. In two metastatic solid tumor models, neoadjuvant intratumoral immunotherapy generated a local T-cell antitumor response that then acted systemically to attack cancer throughout the body. In addition, the importance of timing between neoadjuvant immunotherapy and surgical resection was established, as well as the increased therapeutic power of adding systemic anti-PD1 antibody. The combination of local and systemic immunotherapy generated an additional survival benefit due to synergistic inhibitory effect on tumor-associated macrophages. These results provide a strong rationale for translating this neoadjuvant intratumoral immunotherapy to the clinical setting, especially in conjunction with established checkpoint inhibitors.

SIGNIFICANCE

This work demonstrates the ability of neoadjuvant intratumoral immunotherapy to target local and distant metastatic disease and consequently improve survival.

Exploring the Evolving Scope of Neoadjuvant Immunotherapy in NSCLC

While lung cancer remains the leading cause of cancer death worldwide, lung cancer mortality has notably decreased in the past decade. Immunotherapy with immune checkpoint inhibitors have played a noteworthy role in contributing to this improved survival, particularly for patients with non-small cell lung cancer (NSCLC). However, until now the benefits have primarily been seen in patients with advanced or metastatic disease. Several recent early phase and ongoing phase III trials have been assessing whether the treatment benefit of immunotherapy in NSCLC can extend to the neoadjuvant setting for resectable diseases. In this comprehensive narrative review, we evaluate the most recent efficacy and safety data from these studies. We also outline questions that will need to be further examined to legitimate neoadjuvant immunotherapy's role in NSCLC treatment, including the best surrogate marker of response, the incorporation of liquid biopsy for disease monitoring, the ability to be combined with other treatment modalities, the need for further adjuvant therapy, and potential future treatment combinations.

Neoadjuvant PD-1 inhibitor combines with chemotherapy versus neoadjuvant chemotherapy in resectable squamous cell carcinoma of the lung

BACKGROUND

A single-agent of anti programmed cell death 1/programmed cell death ligand 1 (anti-PD-1/PD-L1) therapy has been explored for resectable lung cancer before surgery. However, the effectiveness and safety of neoadjuvant programmed cell death 1 (PD-1) blockade combined with chemotherapy have not been published.

METHODS

Twenty-one consecutive patients with potentially resectable squamous cell carcinoma of the lung who received neoadjuvant therapy followed by surgery in Beijing Cancer Hospital were included in this study. Eight patients received two cycles of neoadjuvant platinum-based doublet chemotherapy combined with anti-programmed cell death 1 (anti-PD-1) therapy, while 13 patients received two cycles of neoadjuvant platinum-based doublet chemotherapy only. Chest computed tomography was repeated before neoadjuvant treatment and surgery. Adverse events were monitored. The major pathological response (MPR) rate was determined after surgery. Selected specimens were sent for immunohistochemical and multiplex immunofluorescence analyses, and T-cell receptor DNA sequencing.

RESULTS

Compared with neoadjuvant chemotherapy alone, the combination of PD-1 blockade and chemotherapy increased the pathological complete response rate (37.5% vs. 7.69%) and MPR rate (50% vs. 38.46%). The pathological and radiological evaluations are not consistent. No unknown adverse effects were reported for all the patients. More tumor infiltrating lymphocytes were observed in patients who received PD-1 blockade. No unknown pathological features associated with PD-1 blockade were found. Immune suppression in the peritumoral spaces around the residual tumor cells was observed. The amino acid sequences of the T-cell receptors are not significantly shared among the patients.

CONCLUSIONS

The combination of neoadjuvant chemotherapy and PD-1 blockade is safe and feasible, and might indicate an increased MPR and pathological complete response rate. More investigations are needed for the best combination of the neoadjuvant therapy.

Important Surgical and Clinical End Points in Neoadjuvant Immunotherapy Trials in Resectable NSCLC

Neoadjuvant immunotherapy may improve outcomes in patients with resectable NSCLC and is being evaluated in phase 2 and 3 studies. Nevertheless, preoperative treatment postpones resection; the potential for increased surgical complexity and greater intra- and postoperative morbidity and mortality is an additional consideration. In studies primarily designed to evaluate efficacy, the impact of neoadjuvant immunotherapy on surgery is based on parameters that are poorly defined and reported differently between studies. Defining and reporting common end points among trials would improve understanding and facilitate cross-comparison of different immunotherapy regimens and may facilitate wider adoption of induction therapies by surgeons and oncologists. We propose several surgical end points and related metrics for neoadjuvant immunotherapy in resectable NSCLC. These include the periods from screening to treatment initiation and from last neoadjuvant dose to surgery; reporting of the allowable window for surgery to preclude masking delays caused by induction treatment-related toxicity; complete resection (R0) rate; preoperative downstaging; a standardized list of immune-related adverse events and associated delay to surgery; preoperative attrition; postoperative attrition before adjuvant therapy; and postoperative 30- and 90-day mortality and morbidity rates. Intraoperative end points (blood loss, duration, and type of surgery) and our proposed system of grading complexity based on lymphadenopathy and fibrosis would allow quantitation of technical difficulty and quality of oncologic resection. In conclusion, the standardization, reporting, and prospective inclusion of these end points in study protocols would provide a comparative overview of the impact of different neoadjuvant immunotherapy regimens on surgery and ultimately clinical oncologic outcomes in resectable NSCLC.

Revisiting neoadjuvant therapy in non-small-cell lung cancer

Despite the rapidly evolving treatment landscape in advanced non-small-cell lung cancer (NSCLC), developments in neoadjuvant and adjuvant treatments have been nascent by comparison. Establishing overall survival benefit in the early-stage setting has been challenging because of the need for large trials and long-term survival data. Encouraged by improved treatment outcomes with a biomarker-driven approach in advanced NSCLC, and recognising the need to improve survival outcomes in early-stage NSCLC, there has been renewed interest in revisiting neoadjuvant strategies. Multiple neoadjuvant trials with targeted therapy and immunotherapy, either alone or in combination with chemotherapy, have yielded unique insights into traditional response parameters, such as the discordance between RECIST response and pathological response, and expanded opportunities for biomarker discovery. With further standardisation of trial endpoints across studies, coupled with the implementation of novel technologies including radiomics and digital pathology, individual risk-stratified neoadjuvant treatment approaches are poised to make a striking impact on the outcomes of early-stage NSCLC.

Lung Cancer Surgery after Neoadjuvant Immunotherapy

In early-stage lung cancer, recurrences are observed even after curative resection. Neoadjuvant immunotherapy might be a promising approach to eliminate micrometastasis and to potentially reduce recurrence rates and improve survival. Early trials have shown encouraging rates of pathologic response to neoadjuvant therapy and have demonstrated that surgery can be safely performed after neoadjuvant immunotherapy with various agents and in combination with chemo-(radio)therapy. However, whether these response rates translate into improved disease-free survival rates and overall survival rates remains to be determined by ongoing phase III studies.

Regulation of RAD51 at the Transcriptional and Functional Levels: What Prospects for Cancer Therapy?

The RAD51 recombinase is a critical effector of Homologous Recombination (HR), which is an essential DNA repair mechanism for double-strand breaks. The RAD51 protein is recruited onto the DNA break by BRCA2 and forms homopolymeric filaments that invade the homologous chromatid and use it as a template for repair. RAD51 filaments are detectable by immunofluorescence as distinct foci in the cell nucleus, and their presence is a read out of HR proficiency. RAD51 is an essential gene, protecting cells from genetic instability. Its expression is low and tightly regulated in normal cells and, contrastingly, elevated in a large fraction of cancers, where its level of expression and activity have been linked with sensitivity to genotoxic treatment. In particular, BRCA-deficient tumors show reduced or obliterated RAD51 foci formation and increased sensitivity to platinum salt or PARP inhibitors. However, resistance to treatment sets in rapidly and is frequently based on a complete or partial restoration of RAD51 foci formation. Consequently, RAD51 could be a highly valuable therapeutic target. Here, we review the multiple levels of regulation that impact the transcription of the RAD51 gene, as well as the post-translational modifications that determine its expression level, recruitment on DNA damage sites and the efficient formation of homofilaments. Some of these regulation levels may be targeted and their impact on cancer cell survival discussed.

Evaluation of Pathologic Response in Lymph Nodes of Patients With Lung Cancer Receiving Neoadjuvant Chemotherapy

INTRODUCTION

Major pathologic response (MPR), defined as residual viable tumor of less than or equal to 10%, currently serves as a surrogate end point for survival for patients with resectable NSCLC after neoadjuvant chemotherapy. However, the significance of pathologic response in lymph nodes harboring metastatic tumors in such patients remains uncertain. Therefore, we studied the effect of neoadjuvant chemotherapy on resected positive lymph nodes and determined if the degree of pathologic response in the lymph nodes alone (LN-MPR) or in combination with that of the primary tumor (PT-MPR) was able to predict the outcome.

METHODS

A total of 75 patients with NSCLC who underwent neoadjuvant chemotherapy and completed surgical resection were included in this study. Tissue specimens were retrospectively evaluated by two pathologists blinded to the patients' treatments and outcomes. Specimens were reviewed for the degree of pathologic response in the primary tumor and in any involved lymph nodes. The prognostic performance of LN-MPR alone or in combination with PT-MPR with respect to overall survival (OS) was evaluated using the Kaplan-Meier method and Cox regression model.

RESULTS

LN-MPR was significantly predictive of long-term OS after neoadjuvant chemotherapy. A combination of PT-MPR with LN-MPR was significantly associated with outcome and allowed stratification of patients into three prognostic groups (p = 0.001).

CONCLUSIONS

LN-MPR in isolation is a reliable predictor of OS in patients with NSCLC receiving neoadjuvant chemotherapy. A combination of LN-MPR with PT-MPR seems to correlate well with the outcome and can be used to predict prognosis in this patient population.

Agreement on Major Pathological Response in NSCLC Patients Receiving Neoadjuvant Chemotherapy

INTRODUCTION

We have suggested that major pathologic response (MPR) could serve as a surrogate endpoint for survival and provide rapid means of comparing different neoadjuvant treatment regimens. Here, we confirm that MPR is predictive of long-term overall survival (OS) in patients with non-small-cell lung cancer (NSCLC) who underwent neoadjuvant chemotherapy and surgical resection, to assess agreement on MPR between 2 observers, and to determine the minimum number of slides needed to obtain an accurate determination of MPR.

PATIENTS AND METHODS

We identified 151 patients with NSCLC who had been treated with neoadjuvant chemotherapy followed by complete surgical resection from 2008 to 2012. Tissue specimens were retrospectively evaluated by 2 pathologists who had been blinded to patients' treatment and outcome. We assessed the relationships between MPR and OS, the levels of agreement between the pathologists, and determined the number of slides needed to obtain an accurate determination of MPR.

RESULTS

Our results reveal that MPR examined by either observer 1 (experienced) or by observer 2 (trained) was significantly predictive of long-term OS after neoadjuvant chemotherapy. MPR was associated with long-term OS in patients with NSCLC undergoing neoadjuvant chemotherapy on multivariable analysis (hazard ratio 2.68; P = .01). The levels of agreement between 2 pathologists were high after direct in-person training by one pathologist or the other (R² = 0.994). Our data suggest that at least 3 slides should be read to accurately determine MPR.

CONCLUSIONS

MPR is significantly predictive of long-term OS in neoadjuvant chemotherapy-treated patients with NSCLC. MPR may serve as a surrogate endpoint for evaluating novel chemotherapies and immunotherapy response in biomarker-driven translational clinical trials.

Role of Rad51 and DNA repair in cancer: A molecular perspective

The maintenance of genome integrity is essential for any organism survival and for the inheritance of traits to offspring. To the purpose, cells have developed a complex DNA repair system to defend the genetic information against both endogenous and exogenous sources of damage. Accordingly, multiple repair pathways can be aroused from the diverse forms of DNA lesions, which can be effective per se or via crosstalk with others to complete the whole DNA repair process. Deficiencies in DNA healing resulting in faulty repair and/or prolonged DNA damage can lead to genes mutations, chromosome rearrangements, genomic instability, and finally carcinogenesis and/or cancer progression. Although it might seem paradoxical, at the same time such defects in DNA repair pathways may have therapeutic implications for potential clinical practice. Here we provide an overview of the main DNA repair pathways, with special focus on the role played by homologous repair and the RAD51 recombinase protein in the cellular DNA damage response. We next discuss the recombinase structure and function per se and in combination with all its principal mediators and regulators. Finally, we conclude with an analysis of the manifold roles that RAD51 plays in carcinogenesis, cancer progression and anticancer drug resistance, and conclude this work with a survey of the most promising therapeutic strategies aimed at targeting RAD51 in experimental oncology.

Clinical-Pathologic Correlation and Guideline Concordance in Resectable Non-Small Cell Lung Cancer

BACKGROUND

Accurate staging of non-small cell lung cancer (NSCLC) is critical for identifying patients who will benefit from multimodality therapy. This study evaluated clinical-pathologic correlation and its effects on receipt of guideline-concordant therapy in a national cohort.

METHODS

A retrospective cohort study of patients with surgically resected NSCLC in the National Cancer Database (NCDB) between 2004 and 2014 was conducted. Primary tumor and nodal staging information was analyzed in patients who underwent upfront surgery and neoadjuvant therapy to calculate correlation between clinical and pathologic stages and estimate downstaging rate. Staging accuracy and Spearman's rank correlation coefficients were calculated. Multivariable Cox regression was used to evaluate the association between receipt of guideline-concordant therapy and overall risk of death.

RESULTS

Among 82,999 patients, correlation between clinical and pathologic stages was strong (r = 0.69). Correlation of primary tumor staging was high (71.2%-84.5%). The positive predictive value of nodal staging was 78.2%. Neoadjuvant therapy was associated with downstaging in tumor stage (T1, 1.5%; T2, 22.6%; T3, 28%; T4, 42%) and 17.3% of positive nodes. Patients with stage I disease had high rates of guideline-concordant treatment (IA, 97.4%; and IB, 97.9%). Patients with stage IIA to IIIA disease had lower rates of guideline concordance. Receipt of guideline-concordant care was associated with a significantly lower risk of death (hazard ratio, 0.84; 95% confidence interval, 0.80-0.87).

CONCLUSIONS

Clinical staging modalities are reasonably accurate. However, less than one half of patients with stage IIA to IIIA NSCLC receive guideline-concordant therapy, and this deficiency is associated with inferior survival. Identifying factors contributing to these differences is crucial to improve outcomes.

In silico perturbation of drug targets in pan-cancer analysis combining multiple networks and pathways

The knowledge of cancer cell response to conventional therapies is crucial in order to choose the correct therapy of patients affected by cancer. The major problem is generally attributed to the lack of specific biological processes able to predict the therapy efficacy. Here, we optimized a computational method for the analysis of gene networks able to detect and quantify the effects of a drug in a pan-cancer study. Overall, our method, using several network topological measures has identified a cancer gene network with a key role in biological processes. The gene network, able to classify with a good performance cancer vs normal samples, was modulated in silico to evaluate the effects of new or approved drugs. This computational model could offer an interesting hint to decipher molecular mechanisms contributing to resistance or inefficacy of drugs.

The challenges of evaluating predictive biomarkers using small biopsy tissue samples and liquid biopsies from non-small cell lung cancer patients

The list of theranostic biomarkers for the care of patients with advanced stage or metastatic non-small cell lung cancer has lengthened considerably these last few years. Moreover, the advances in therapeutics will certainly increase the number and complexity of these tests performed in laboratories in the near future. In addition, the methods for investigation of biomarkers that require access to biological tissue are less and less invasive with the consequential increase in the use of small-sized tissue biopsies and cytological and blood samples. Thus, each laboratory must master the management of the biological samples according to the number and type of tests to be performed. This review will provide an update of the difference challenges facing pathologists and biologist in responding to the issues related to new treatments. These challenges concern: (I) the management of the pre-analytical phase; (II) the appropriate choice of the technological approach; (III) the performance of quality control; (IV) the mastering of the delay in obtaining the results; and (V) the economic model of the laboratory.