Two Germline Pathogenic Variants in Cancer Susceptibility Genes and Their Null Implication in Breast Cancer Pathogenesis: The Importance of Tumoral Homologous Recombination Deficiency Testing

Homologous recombination proficiency in patients with breast cancer despite germline PALB2/RAD51C pathogenic variants.

Association between missense variants of uncertain significance in the CHEK2 gene and hereditary breast cancer: a cosegregation and bioinformatics analysis

Inherited mutations in the CHEK2 gene have been associated with an increased lifetime risk of developing breast cancer (BC). We aim to identify in the study population the prevalence of mutations in the CHEK2 gene in diagnosed BC patients, evaluate the phenotypic characteristics of the tumor and family history, and predict the deleteriousness of the variants of uncertain significance (VUS). A genetic study was performed, from May 2016 to April 2020, in 396 patients diagnosed with BC at the University Hospital Lozano Blesa of Zaragoza, Spain. Patients with a genetic variant in the CHEK2 gene were selected for the study. We performed a descriptive analysis of the clinical variables, a bibliographic review of the variants, and a cosegregation study when possible. Moreover, an in-depth bioinformatics analysis of CHEK2 VUS was carried out. We identified nine genetic variants in the CHEK2 gene in 10 patients (two pathogenic variants and seven VUS). This supposes a prevalence of 0.75% and 1.77%, respectively. In all cases, there was a family history of BC in first- and/or second-degree relatives. We carried out a cosegregation study in two families, being positive in one of them. The bioinformatics analyses predicted the pathogenicity of six of the VUS. In conclusion, CHEK2 mutations have been associated with an increased risk for BC. This risk is well-established for foundation variants. However, the risk assessment for other variants is unclear. The incorporation of bioinformatics analysis provided supporting evidence of the pathogenicity of VUS.

Germline TP53 pathogenic variants and breast cancer: A narrative review

Approximately 10% of breast cancers are associated with the inheritance of a pathogenic variant (PV) in one of the breast cancer susceptibility genes. Multiple breast cancer predisposing genes, including TP53, are responsible for the increased breast cancer risk. Tumor protein-53 (TP53) germline PVs are associated with Li-Fraumeni syndrome, a rare autosomal dominant inherited cancer predisposition syndrome associated with early-onset pediatric and multiple primary cancers such as soft tissue and bone sarcomas, breast cancer, brain tumors, adrenocortical carcinomas and leukemias. Women harboring a TP53 PV carry a lifetime risk of developing breast cancer of 80-90%. The aim of the present narrative review is to provide a comprehensive overview of the criteria for offering TP53 testing, prevalence of TP53 carriers among patients with breast cancer, and what is known about its prognostic and therapeutic implications. A summary of the current indications of secondary cancer surveillance and survivorship issues are also provided. Finally, the spectrum of TP53 alteration and testing is discussed. The optimal strategies for the treatment of breast cancer in patients harboring TP53 PVs poses certain challenges. Current guidelines favor the option of performing mastectomy rather than lumpectomy to avoid adjuvant radiotherapy and subsequent risk of radiation-induced second primary malignancies, with careful consideration of radiation when indicated post-mastectomy. Some studies suggest that patients with breast cancer and germline TP53 PV might have worse survival outcomes compared to patients with breast cancer and wild type germline TP53 status. Annual breast magnetic resonance imaging (MRI) and whole-body MRI are recommended as secondary prevention.

Clinical and psychological implications of secondary and incidental findings in cancer susceptibility genes after exome sequencing in patients with rare disorders

Background/Objectives

Exome sequencing may identify pathogenic variants unrelated with the purpose of the analysis. We investigated the frequency of secondary and incidental findings (SF/IF) in cancer susceptibility genes (CSG), their clinical actionability and the psychological impact in individuals with an SF/IF (cases) compared with individuals tested due to their cancer history (controls).

Methods

This study analysed 533 exomes ordered for non-cancer conditions. Medical records were reviewed for clinical actionability of SF/IF. Psychological impact was analysed using the Multidimensional Impact of Cancer Risk Assessment (MICRA) scale and compared between cases and controls with a propensity score weighting method.

Results

The frequency of SF/IF in CSG was 2.1% (95% CI 1.1% to 3.8%): threeBRCA2, threePMS2, twoSDHB, and one each inBRCA1,MLH1andRAD51C. Among the relatives, 18 were carriers. Twenty enrolled for surveillance, and a neoplasm was diagnosed in 20%: three paragangliomas and one breast cancer. Cases presented higher MICRA mean scores than controls (21.3 vs 16.2 in MICRA total score, 6.3 vs 4.2 in the distress subscale, and 8.3 vs 6.6 in the uncertainty subscale; all p<0.001).

Conclusion

SF/IF in CSG were identified in 2.1% of patients. Despite a numerically higher psychological impact, the identification of SF/IF allowed early detection and cancer prevention in families without cancer history.

Genetic and functional homologous repair deficiency as biomarkers for platinum sensitivity in TNBC: A case report

Triple-negative breast cancer is the most aggressive subtype of mammary carcinoma. In the early stage, neoadjuvant chemotherapy (NAC) is the standard of care for prognostic stratification and the best adjuvant treatment strategy. A 30-year-old female presented in the emergency room because of a gigantic right breast associated with an ulcerated lump at the upper quadrants. The right axillary nodes were palpable. An ultrasound was performed, showing the ulcerated neoformation with enlarged right axillary lymph nodes observed to level III. A core biopsy of the breast lesion was performed, and the pathological examination revealed a nonspecial type, grade 3, invasive, triple-negative breast cancer. No distant disease was found in the PET-CT scan. A germline genetic panel by next-generation sequencing identified a likely pathogenic variant in RAD51D (c.898C>T). Assessment of the functionality of the DNA homologous recombination repair pathway by RAD51 foci in the tumor revealed a profile of homologous recombination deficiency. NAC consisting of weekly carboplatin and paclitaxel followed by dose-dense doxorubicin/cyclophosphamide was performed with a complete metabolic response achieved in the PET-CT scan. The patient underwent a modified radical mastectomy plus axillary lymphadenectomy with a pathological complete response in the breast and axilla and remains disease-free after 2 years of follow-up. We report a young female with a triple-negative breast cancer stage cT4bN3M0 and a hereditary pathogenic mutation in RAD51D. The tumor was highly proliferative and homologous recombination-deficient by RAD51. The patient received platinum-based NAC, achieving a pathologic complete response. More effort should be made to identify predictive functional biomarkers of treatment response, such as RAD51 foci, for platinum sensitivity.

Current Systemic Treatments for the Hereditary Cancer Syndromes: Drug Development in Light of Genomic Defects

Advances in the genetic basis of different tumors have led to identification of tumor vulnerabilities that can be turn into targeted therapies. In this regard, PARP inhibitors cause synthetic lethality with tumors harboring BRCA1 or BRCA2 genetic alterations. On the other hand, tumors with microsatellite instability, either due to germline or sporadic alterations, are candidates for immune checkpoint inhibitors. Finally, patients with von Hippel-Lindau disease who carry a germline alteration in the VHL gene may benefit form belzutifan, a hypoxia-inducible factor 2 alpha inhibitor. Overall, research on the underlying pathological mechanisms of these tumors has provided new therapeutic opportunities that might be expanded to other sporadic tumors with similar biology.

Shedding of ctDNA, radiomics assessment of tumor disease volume (TDV), and concordance of mutations (mut) in synchronous liquid and tumor biopsies in metastatic breast cancer (MBC)

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Background: Genomic alterations driving MBC progression may be better captured by ctDNA reflecting clonal evolution, but it is currently unknow whether ctDNA analysis can replace tumor sequencing for clinical decision purposes. Aim: to study the concordance between mut in synchronous plasma and tumor samples prospectively collected from patients (pts) with MBC progressing on their last systemic therapy. Methods: MiSeq Amplicon-based NGS (custom panel of 60 cancer-related genes; BRCA1/2 and PALB2 not included) was performed in both tumor biopsy and plasma. The concordance of ESCAT Tier I and II mut ( PIK3CA, AKT1, ERBB2, ESR1, PTEN) was determined and correlated with mutant allele fraction (MAF), TDV, and clinical features. Findings from liquid biopsies were classified as true positive (TP-ctDNA) if a given mut was detected in both tumor and plasma and false negative (FN-ctDNA) if only in the tumor. TDV: all metastasis volume assessed by CT scan (excluding sclerotic bone metastasis), and analyzed by an experienced radiologist using the 3DSlicer semiautomatic segmentation tool (TDV = pixel size x number of pixels). Non-shedding cases were those where any mut was detected in tumor but none in plasma. Results: 88 cases were collected (luminal 64, HER2+ 17, triple negative 7). Median age at diagnosis 49 years (range 28-80). Radiomics assessment could be performed in 78/88 cases. The plasma/tissue concordance at case level was 74%. Discordance came from 23 cases; in 15 cases mut was only found in tissue and in 8 cases it was only detected in plasma. At gene level, PIK3CA had the highest concordance (79%); in ESR1 it was 52%. Higher concordance associated with non-luminal subtype (OR 0.08, 95%CI 0.002 – 0.59) and shorter interval between primary diagnosis and metastatic relapse (20.3 vs 51 months; p =.02), but not with MAF. FN-ctDNA occurred in 15/49 cases (31%) and associated with luminal subtype (p =.02), but not with other clinical variables. Non-shedding cases associated with older age (p =.03), luminal subtype (p =.007), low TDV (p =.0006) and < 3 metastatic sites (p =.05). In patients with visceral metastasis (n = 45), higher TDV associated with lower probability of FN-ctDNA (p =.03). All non-luminal subtypes were shedders and all but one were TP-ctDNA. In multivariate analysis, higher probability of TP-ctDNA in luminal tumors associated with tumor sampling from a progressing lesion (OR 10.8; 95% 1.5 – 122; p =.03) and shorter interval between diagnosis of metastatic disease and biopsy (OR 0.96, 95% CI 0.92 – 0.99; p =.03). Conclusions: Our results suggest that ctDNA can detect a significant proportion of clinically relevant mut in MBC. Patients’ characteristics, tumor subtype, type of gene, and tumor volume should be integrated with ctDNA results to better inform clinical decisions.

How Could Antibiotics, Probiotics, and Corticoids Modify Microbiota and Its Influence in Cancer Immune Checkpoint Inhibitors: A Review

Immunotherapy has become a new paradigm in oncology, improving outcomes for several types of cancer. However, there are some aspects about its management that remain uncertain. One of the key points that needs better understanding is the interaction between immunotherapy and gut microbiome and how modulation of the microbiome might modify the efficacy of immunotherapy. Consequently, the negative impact of systemic antibiotics and corticosteroids on the efficacy of immunotherapy needs to be clarified.

Surrogates of response to treatment of non-small cell lung cancer with immunotherapy: Toxicity and leukocyte ratios—Experience of a center

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Background: Immunotherapy is proposed as a therapeutic novelty in metastatic non-small cell lung cancer (NSCLC), in many cases already in front line. It presents different adverse effects than traditional schemes, due to the stimulation of the immune system. There is a possible relationship between toxicity and response. Neutrophil-to-lymphocyte ratio (NLR) as a possible predictive factor of response. Objectives: Evaluating the response according to the toxicity degree in NSCLC patients in real clinical practice. Analyze whether pretreatment NLR high patients have a worse prognosis. Methods: Observational, retrospective, analytical, single-center study. HCULB stage IV NSCLC patients with inmunotherapy treatment during 2016-2018. Descriptive and multivariate analysis. Toxicity grade: CTCAE version 4.0. Response assessment: RECIST 2.0 and immunorelated criteria. Toxicity degree and response (global and individualized results according to treatment and histology). Neutrophil-to-lymphocyte ratio and response. Results: N = 43 patients (35 men, 8 women). Average age 64 years. Response: 3 complete response (CR) (toxicity ≥2), 13 partial response (PR) (toxicity ≥1), 13 stable disease (SD), 12 progression (P) (only 4 toxicity and ≤2), 2 not evaluated. Hypothyroidism as the most common irAE. Relationship between toxicity and response: the absence of irAEs conditions worse prognosis p < 0.05. Histology: 25 adenocarcinoma [18 with irAES (1 CR, 7 PR, 8 SD,) and 7 without (1 SD, 5 P, 1 no ev.)]; 17 squamous [13 with irAES (1 CR, 6 PR, 4 SD) and 4 without (3 P, 1 no ev.)]; 1 adenosquamous with irAES and CR. Drug: Atezolizumab N = 8 [6 with irAES (2 PR, 3 SD, 1 P) and 2 without (both P)], Nivolumab N = 16 [9 with irAES (1 CR, 3 PR, 3 SD, 2 P) and 7 without (1 SD, 4 P, 2 no ev.)], Pembrolizumab N = 19 [17 with irAEs (2 CR, 8 PR, 6 SD, 1 P) and 2 without (both P)]. Significant positive correlation between toxicity and response (p < 0.001) R = 0.067, (CI 99% 0.378-0.837), regardless of histology and drug. It is observed a better response in those patients who presented a NRL close to 3 or less at the beginning of treatment. On the contrary, it is observed that subjects with NRL greater than 4 obtained worse results when they were treated with immunotherapy. Conclusions: The appearance of irAES like a response indicator of immune system, seem to conditione better evolution. In contrast, the absence of toxicity predicts a worse prognosis. Further studies with a larger sample are needed to confirm our findings about the predictive value of NLR and optimize therapeutic regimens if necessary.

Hereditary breast cancer associated with the CHEK2 gene: Study through NGS in a Spanish cohort

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Background: Inherited mutations in the CHEK2 gene have been associated with an increased lifetimerisk of develop breast cancer (BC). The main objective of the study is to identify in our population the prevalence of mutations in the CHEK2 gene in diagnosed BC patients, as well as to evaluate the phenotypic characteristics of the tumour and family history. Methods: A genetic study was performed in 396 patients diagnosed of BC at the University Hospital Lozano Blesa of Zaragoza (Spain). We selected 9 patients with genetic variants in the CHEK2 gene and performed a descriptive analysis of the clinical variables, a bibliographic review of the genetic variants and a co-segregation study. Results: We identified 2 pathogenic variants ( CHEK2 c.349 A>G and c.507delT) and 6 variants of uncertain significance (VUS). The genotypic characteristics of the VUS are summarized in the table. In all cases there was a family history of BC in first and /or second degree relatives. The variant cosegregated with the disease in one of the families. Conclusions: The pathogenic missense variant c.349A>G was found in two families. This is a rare missense variant. Studies have shown that this variant had a significant impact on the protein based on in silico prediction and has been associated with BC. In our study, this variant was found in a patient with renal carcinoma and was identified in a proband with a strong family history of pancreatic and ovarian cancer (OC). However, there aren’t exist data about the risk of developing other cancer, different of BC, with this specific mutation. The other pathogenic variant detected was CHEK2 c.507delT in a family with history of BC and OC. This variant is a frameshift mutation, predicted to cause loss of normal protein function. CHEK2 507delT was reported in one of 12 BC families in one series and is possible its relation with OC. With regard to the VUS the cosegregation analysis in selected families may help understand if a variant could have played a role in developing cancer. In conclusion, CHEK2 mutations have been associated with increased risk for BC. However, the frequency of carriers may vary depending on the population, and different mutations may be associated with different cancer risks. More studies are needed to establish a complete range of risks associated with CHEK2 mutations. [Table: see text]

Subclassification of the intermediate-risk group in patients with advanced renal cell carcinoma

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Background: Renal cell carcinoma (RCC) have low prevalence but it incidence is increasing. For a correct therapeutic approach, it is important to carry out a correct prognostic stratification. Several prognostication systems have been proposed. One of the most commonly used is the one developed by Heng. It is based on IMDC database. This classification includes six prognostic factors (hemoglobin, neutrohils, platelets, serum calcium, Karnosky Performance Status and time from diagnosis to initiaton treatment) to divide patients into three gorups. The relevance of IMDC prognostic criterio, in the era of immunotherapy, remains to be established. In the absence of alternative criteria, these prognostication system continue to be used. A great prognostic disparity has been observed in the intermediate prognosis group. This raises the need to divide this group into two. Thus, patients included in it would be better selected. Methods: Observational, single-center, retrospective study, based on a cohort of 107 patients with advanced RCC, recruited from January 2006 to December 2019. Main objective: Evaluate whether survival of patients with intermediate prognosis (treated with antiangiogenic in first-line) is different depending on the presence of one or two prognostic factors. Descriptive and survival analysis (OS and PFS) were performed. In addition, the influence of prognostic factors on OS and PFS were compared using the log-rank test and Cox regression. Results: In the overall population, median overall survival (OS) was 26.86 months (95% CI: 21.09-32.63) and median PFS was 18.41 months (95% CI: 14.02-22.79). Median OS were, in favorable-risk 42.24 months (95% CI: 29.62-54.62), in intermediate-risk 27,24 (95% CI: 19.44-35-03) and in poor-risk 8.00 (95% CI: 4.54-11.45). Median PFS were in favorable-risk 30.53 months (95% CI:20.92-40.13), in intermediate-risk 17,16 (95% CI:11.54-22.78) and poor-risk 6.13 (95% CI:3.02-9.25). Median OS and PFS, in patients with intermediate-risk, with a single risk factor were 33.79 (95% CI 23.17-44.41) and 20.97 months (95% CI 13.35-28.59), compared to 14.88 (95% CI 8.80-20.95) and 10.59 months (95% CI 4.87-16.32) in those with two risk factors. The results were statistically significant in OS (p = 0.01) and PFS (p = 0.037). Conclusions: The differences in median OS and PFS, within the intermediate prognosis group (1 or 2 RF), confirm the existence of two subgroups of patients. Patients with 1 RF are similar to those with favorable-risk. These results are important since, the presence of 1 or 2 RF, would condition the choice of TKIs as part of the first-line treatment combination. More studies are needed to better subclassify the intermediate risk group when optimizing the best treatments for each patient.

From Tumor Mutational Burden to Blood T Cell Receptor: Looking for the Best Predictive Biomarker in Lung Cancer Treated with Immunotherapy

Simple Summary

Immune control inhibitor drugs (anti-PD1/PD-L1/CTLA-4) (ICIs) are showing efficacy in the treatment of lung cancer. Currently the only biomarker with clinical utility for ICIs, such as the expression of PDL1, does not appear to be perfect or effective. Our working group is conducting a pilot study in lung cancer patients receiving ICIs with the aim of analyze the factors that affect the sensitivity of the immunotherapy in lung Cancer. Tumor Mutational Burden (TMB) and the sequencing of the T Cell Receptor (TCR) repertoire in peripheral blood have been postulated as predictive biomarkers of efficacy of immunotherapy. The review focusses on the predictive value of TMB for clinical responses to ICIs and discusses its clinical need after a discussion of the limitations. TCR CDR3 beta analysis and parameters such as clonality and TCR convergence may be good alternatives. For the moment, the combination of biomarkers may be the optimal tool.

Abstract

Despite therapeutic advances, lung cancer (LC) is one of the leading causes of cancer morbidity and mortality worldwide. Recently, the treatment of advanced LC has experienced important changes in survival benefit due to immune checkpoint inhibitors (ICIs). However, overall response rates (ORR) remain low in unselected patients and a large proportion of patients undergo disease progression in the first weeks of treatment. Therefore, there is a need of biomarkers to identify patients who will benefit from ICIs. The programmed cell death ligand 1 (PD-L1) expression has been the first biomarker developed. However, its use as a robust predictive biomarker has been limited due to the variability of techniques used, with different antibodies and thresholds. In this context, tumor mutational burden (TMB) has emerged as an additional powerful biomarker based on the observation of successful response to ICIs in solid tumors with high TMB. TMB can be defined as the total number of nonsynonymous mutations per DNA megabases being a mechanism generating neoantigens conditioning the tumor immunogenicity and response to ICIs. However, the latest data provide conflicting results regarding its role as a biomarker. Moreover, considering the results of the recent data, the use of peripheral blood T cell receptor (TCR) repertoire could be a new predictive biomarker. This review summarises recent findings describing the clinical utility of TMB and TCRβ (TCRB) and concludes that immune, neontigen, and checkpoint targeted variables are required in combination for accurately identifying patients who most likely will benefit of ICIs.

Microbiota and Lung Cancer. Opportunities and Challenges for Improving Immunotherapy Efficacy

The advances in molecular biology and the emergence of Next Generation Sequencing (NGS) have revealed that microbiome composition is closely related with health and disease, including cancer. This relationship affects different levels of cancer such as development, progression, and response to treatment including immunotherapy. The efficacy of immune checkpoint inhibitors (ICIs) may be influenced by the concomitant use of antibiotics before, during or shortly after treatment with ICIs. Nevertheless, the linking mechanism between microbiote, host immunity and cancer is not clear and the role of microbiota manipulation and analyses in cancer management has not been clinically validated yet. Regarding the use of microbiome as biomarker to predict ICI efficacy it has been recently shown that the use of biochemical serum markers to monitor intestinal permeability and loss of barrier integrity, like citrulline, could be useful to monitor microbiota changes and predict ICI efficacy. There are still many unknowns about the role of these components, their relationship with the microbiota, with the use of antibiotics and the response to immunotherapy. The next challenge in microbiome research will be to identify individual microbial species that causally affect lung cancer phenotypes and response to ICI and disentangle the underlying mechanisms. Thus, further analyses in patients with lung cancer receiving treatment with ICIs and its correlation with the composition of the microbiota in different organs including the respiratory tract, peripheral blood and intestinal tract could be useful to predict the efficacy of ICIs and its modulation with antibiotic use.

Intratumoral Versus Circulating Lymphoid Cells as Predictive Biomarkers in Lung Cancer Patients Treated with Immune Checkpoint Inhibitors: Is the Easiest Path the Best One?

The molecular and cell determinants that modulate immune checkpoint (ICI) efficacy in lung cancer are still not well understood. However, there is a necessity to select those patients that will most benefit from these new treatments. Recent studies suggest the presence and/or the relative balance of specific lymphoid cells in the tumor microenvironment (TEM) including the T cell (activated, memory, and regulatory) and NK cell (CD56dim/bright) subsets, and correlate with a better response to ICI. The analyses of these cell subsets in peripheral blood, as a more accessible and homogeneous sample, might facilitate clinical decisions concerning fast prediction of ICI efficacy. Despite recent studies suggesting that lymphoid circulating cells might correlate with ICI efficacy and toxicity, more analyses and investigation are required to confirm if circulating lymphoid cells are a relevant picture of the lung TME and could be instrumental as ICI response biomarkers. This short review is aimed to discuss the recent advances in this fast-growing field.