Multiple targets, germline BRCA1 mutation and HRD in a lung cancer patient: Molecular considerations and treatment decision-making

INTRODUCTION

Several biomarkers are currently available to address targeted treatments in cancer patients, with lung malignancies representing one of the best examples.

CASE DESCRIPTION

We report the case of a patient affected by advanced non-small cell lung cancer with an uncommon histology and a complex biology. The use of a large next-generation sequencing (NGS) NGS panel allowed us to identify an extremely rare BRAF mutation (V600Q), a MET amplification, a high tumor mutational burden, a germline pathogenetic BRCA1 mutation and a homologous recombination deficiency through RAD51 assay. The treatment decision was driven by the abundance of molecular information.

CONCLUSIONS

This case highlights that an attentive and critical evaluation of molecular reports is key for the tailoring of treatment algorithms at the patient-level scale.

Resistance to osimertinib in advanced EGFR-mutated NSCLC: a prospective study of molecular genotyping on tissue and liquid biopsies

BACKGROUND

Resistance to osimertinib in advanced EGFR-mutated non-small cell lung cancer (NSCLC) constitutes a significant challenge for clinicians either in terms of molecular diagnosis and subsequent therapeutic implications.

METHODS

This is a prospective single-centre study with the primary objective of characterising resistance mechanisms to osimertinib in advanced EGFR-mutated NSCLC patients treated both in first- and in second-line. Next-Generation Sequencing analysis was conducted on paired tissue biopsies and plasma samples. A concordance analysis between tissue and plasma was performed.

RESULTS

Sixty-five advanced EGFR-mutated NSCLC patients treated with osimertinib in first- (n = 56) or in second-line (n = 9) were included. We managed to perform tissue and liquid biopsies in 65.5% and 89.7% of patients who experienced osimertinib progression, respectively. Acquired resistance mechanisms were identified in 80% of 25 patients with post-progression samples, with MET amplification (n = 8), EGFR C797S (n = 3), and SCLC transformation (n = 2) the most frequently identified. The mean concordance rates between tissue and plasma for the EGFR activating mutation and for the molecular resistance mechanisms were 87.5% and 22.7%, respectively.

CONCLUSIONS

Resistance to osimertinib demonstrated to be highly heterogeneous, with MET amplification the main mechanism. Plasma genotyping is a relevant complementary tool which might integrate tissue analysis for the study of resistance mechanisms.

Notch-Jagged1 signaling and response to bevacizumab therapy in advanced colorectal cancer: A glance to radiomics or back to physiopathology?

Introduction

The Notch intracellular domain (NICD) and its ligands Jagged-1(Jag1), Delta-like ligand (DLL-3) and DLL4 play an important role in neoangiogenesis. Previous studies suggest a correlation between the tissue levels of NICD and response to therapy with bevacizumab in colorectal cancer (CRC). Another marker that may predict outcome in CRC is radiomics of liver metastases. The aim of this study was to investigate the expression of NICD and its ligands and the role of radiomics in the selection of treatment-naive metastatic CRC patients receiving bevacizumab.

Methods

Immunohistochemistry (IHC) for NICD, Jag1 and E-cadherin was performed on the tissue microarrays (TMAs) of 111 patients with metastatic CRC treated with bevacizumab and chemotherapy. Both the intensity and the percentage of stained cells were evaluated. The absolute number of CD4+ and CD8+ lymphocytes was counted in three different high-power fields and the mean values obtained were used to determine the CD4/CD8 ratio. The positivity of tumor cells to DLL3 and DLL4 was studied. The microvascular density (MVD) was assessed in fifteen cases by counting the microvessels at 20x magnification and expressed as MVD score. Abdominal CT scans were retrieved and imported into a dedicated workstation for radiomic analysis. Manually drawn regions of interest (ROI) allowed the extraction of radiomic features (RFs) from the tumor.

Results

A positive association was found between NICD and Jag1 expression (p < 0.001). Median PFS was significantly shorter in patients whose tumors expressed high NICD and Jag1 (6.43 months vs 11.53 months for negative cases; p = 0.001). Those with an MVD score ≥5 (CD31-high, NICD/Jag1 positive) experienced significantly poorer survival. The radiomic model developed to predict short and long-term survival and PFS yielded a ROC-AUC of 0.709; when integrated with clinical and histopathological data, the integrated model improved the predictive score (ROC-AUC of 0.823).

Discussion

These results show that high NICD and Jag1 expression are associated with progressive disease and early disease progression to anti VEGF-based therapy; the preliminary radiomic analyses show that the integration of quantitative information with clinical and histological data display the highest performance in predicting the outcome of CRC patients.

Multicenter Observational Study on Metastatic Non-Small Cell Lung Cancer Harboring BRAF Mutations: Focus on Clinical Characteristics and Treatment Outcome of V600E and Non-V600E Subgroups

Simple Summary

Around 2–4% of lung adenocarcinoma harbors BRAF mutations. Dabrafenib and Trametinib represent the first treatment-choice for BRAF V600E^mut NSCLC, regardless of the line of therapy, while non-V600E^mut receive standard immunotherapy or chemo-immunotherapy. Our real-life multicenter study on 44 BRAF mutant NSCLC responds to the urgent need to characterize this subset of patients in-depth, potentially offering new valuable biological and clinical insights. We specifically focused on similarities/discrepancies between V600E and non-V600E populations, providing consistent data about clinicopathologic characteristics, treatment response, and survival outcome.

Abstract

Introduction: BRAF mutation involved 2–4% of lung adenocarcinoma. Differences in clinicopathologic features and patient outcome exist between V600E and non-V600E BRAF mutated NSCLC. Thus, we sought to assess the frequency and clinical relevance of BRAF mutations in a real-life population of advanced-NSCLC, investigating the potential prognostic significance of distinct genetic alterations. Materials and Methods: The present multicenter Italian retrospective study involved advanced BRAF mutant NSCLC. Complete clinicopathologic data were evaluated for BRAF V600E and non-V600E patients. Results: A total of 44 BRAF^mut NSCLC patients were included (V600E, n = 23; non-V600E, n = 21). No significant differences in survival outcome and treatment response were documented, according to V600E vs. non-V600E mutations, although a trend towards prolonged PFS was observed in the V600E subgroup (median PFS = 11.3 vs. 6.0 months in non-V600E). In the overall population, ECOG PS and age significantly impacted on OS, while bone lesions were associated with shorter PFS. Compared to immunotherapy, first-line chemotherapy was associated with longer OS in the overall population, and especially in the BRAF V600E subtype. Conclusions: Here, we report on real-life data from a retrospective cohort of advanced-NSCLC harboring BRAF alterations. Our study offers relevant clues on survival outcome, therapeutic response, and clinicopathologic correlations of BRAF-mutant NSCLC.

YES1 and MYC amplifications as synergistic resistance mechanisms to different generation ALK-TKIs in advanced NSCLC: brief report of clinical and preclinical proofs

Introduction

ALK tyrosine kinase inhibitors (TKIs) are the standard treatment for advanced ALK-positive NSCLC. Nevertheless, drug resistance inevitably occurs. Here, we report a case of a patient with metastatic ALK-positive lung adenocarcinoma with an impressive resistance to sequential treatment with ALK TKIs mediated by YES1 and MYC amplification in a contest of epithelial-to-mesenchymal transition and high progressive chromosomal instability.

Methods

The patient received, after chemotherapy and 7 months of crizotinib, brigatinib and lorlatinib with no clinical benefit to both treatments. A study of resistance mechanisms was performed with whole exome sequencing on different biological samples; primary cell lines were established from pleural effusion after lorlatinib progression.

Results

At whole exome sequencing analysis, YES1 and MYC amplifications were observed both in the pericardial biopsy and the pleural effusion samples collected at brigatinib and lorlatinib progression, respectively. Increasing chromosomal instability from diagnostic biopsy to pleural effusion was also observed. The addition of dasatinib to brigatinib or lorlatinib restored the sensitivity in primary cell lines; data were confirmed also in H3122_ALK-positive model overexpressing both YES1 and MYC.

Conclusions

In conclusion, YES1 and MYC amplifications are candidates to justify a rapid acquired resistance to crizotinib entailing primary brigatinib and lorlatinib resistance. In this context, a combination strategy of ALK TKI with dasatinib could be effective to overcome a rapid resistance.

miR-21 antagonism reprograms macrophage metabolism and abrogates chronic allograft vasculopathy

Despite much progress in improving graft outcome during cardiac transplantation, chronic allograft vasculopathy (CAV) remains an impediment to long-term graft survival. MicroRNAs (miRNAs) emerged as regulators of the immune response. Here, we aimed to examine the miRNA network involved in CAV. miRNA profiling of heart samples obtained from a murine model of CAV and from cardiac-transplanted patients with CAV demonstrated that miR-21 was most significantly expressed and was primarily localized to macrophages. Interestingly, macrophage depletion with clodronate did not significantly prolong allograft survival in mice, while conditional deletion of miR-21 in macrophages or the use of a specific miR-21 antagomir resulted in indefinite cardiac allograft survival and abrogated CAV. The immunophenotype, secretome, ability to phagocytose, migration, and antigen presentation of macrophages were unaffected by miR-21 targeting, while macrophage metabolism was reprogrammed, with a shift toward oxidative phosphorylation in naïve macrophages and with an inhibition of glycolysis in pro-inflammatory macrophages. The aforementioned effects resulted in an increase in M2-like macrophages, which could be reverted by the addition of L-arginine. RNA-seq analysis confirmed alterations in arginase-associated pathways associated with miR-21 antagonism. In conclusion, miR-21 is overexpressed in murine and human CAV, and its targeting delays CAV onset by reprogramming macrophages metabolism.

Emergence of a HER2-amplified clone during disease progression in an ALK-rearranged NSCLC patient treated with ALK-inhibitors: a case report

Anaplastic lymphoma kinase tyrosine kinase inhibitors (ALK-TKIs) are the standard treatment for advanced ALK-positive non-small cell lung cancer (NSCLC) allowing survivals up to 5 years. However, duration of responses is limited by the almost certain occurrence of drug resistance. Here, we report a case of a never smoker, 59-year-old female with metastatic ALK-positive adenocarcinoma, solid and signet ring patterns, who developed resistance to alectinib, a second-generation ALK-TKI, mediated by HER2 gene amplification. The patient received 22 months of crizotinib as first-line and subsequently 1-year of alectinib therapy. A study of resistance mechanism was performed with next generation sequencing (NGS) on tissue re-biopsy. A HER2-amplified emerging clone was identified by NGS in a liver metastasis and confirmed by fluorescent in situ hybridization (FISH) analysis. The resistant clone was detectable 2 months before disease progression in plasma cell-free DNA (cfDNA) using digital droplet PCR (ddPCR) copy number variation (CNV) assay and it was retrospectively traced in rare cells of the lung primary by FISH. To our best knowledge, this is first evidence of HER2 gene amplification as a resistance mechanism to ALK-TKI in a NSCLC. Future strategies against oncogene-addicted NSCLC might benefit of combined drug treatments, such as ALK and HER2 inhibition.

Optimizing PD-L1 evaluation on cytological samples from advanced non-small-cell lung cancer

Aim: Programmed cell death-ligand 1 (PD-L1) predicts response to immune checkpoint inhibitors in non-small-cell lung cancer (NSCLC) patients. Most NSCLCs are diagnosed at an advanced stage and using minimally invasive diagnostic procedures that yield small biopsies or cytological samples. Methods: Cytological smears and paired histological samples from 52 advanced NSCLC patients were tested for PD-L1 expression by immunocyto/histochemistry (ICC/IHC) and for PD-L1 gene status by FISH. Results: PD-L1 was overexpressed in 9/52 (17%) cytological samples and in seven (13.5%) matched biopsies. The concordance between immunocytochemistry and IHC was 92.3% (48/52; p < 0.001). The concordance between PD-L1 gene status on cytology and histology was 69.2% (18/26; p < 0.001). No correlation between IHC and fluorescence in situ hybridization results was found. Conclusion: Our data support the feasibility and reliability of PD-L1 protein and PD-L1 gene assessment on direct cytological smears from NSCLC patients whenever histological sample are inadequate.

Correlations between tumor-infiltrating and circulating lymphocyte subpopulations in advanced renal cancer patients treated with nivolumab

BACKGROUND

In clinical trials with immunotherapy, histological features such as tumor-infiltrating lymphocytes (TILs) are investigated as potential predictive biomarkers, with the limit of an outdated parameter for a typically dynamic element.

METHODS

This explorative study compared, in metastatic renal cell carcinoma (mRCC) patients, basal pathological data about TILs on diagnostic histological specimens with circulating lymphocyte subpopulations measured before and during therapy with nivolumab.

RESULTS

Of 11 mRCC patients, 5 had low presence of TILs (L-TILs), 3 moderate amount (M-TILs) and 3 high number (H-TILs). Overall, 8 patients had low intratumoral pathological CD4+/CD8+ ratio (LIPR) ≤1 and 3 cases high intratumoral pathological ratio (HIPR) ≥2. Of 8 patients with LIPR, only 2 matched with low circulating CD4+/CD8+ ratio (LCR) ≤1; 5 had high circulating ratio (HCR) ≥2. All 3 cases with HIPR (≥2) conversely had LCR (≤1). Circulating CD4+/CD8+ ratio remained unchanged during therapy (mean -0.12 in 8 weeks). The respective percentage values of CD4+ and CD8+ circulating T cells also remained stable (variation 0%); the absolute value of CD4+ was more likely to increase (mean +46.3/mm3); the level of CD8+ tended to slightly decrease (mean -6.5/mm3). No correlation of lymphocyte subpopulations with treatment outcome was found. Of note, we did not evidence correspondence between histopathological and circulating findings in terms of T-lymphocyte subpopulations, also suggesting the inconsistency of circulating data in terms of relative variations.

CONCLUSIONS

Considering the likely high dynamism of TILs, rebiopsy before therapy might be proposed to assess the utility of TILs characterization for predictive purpose. (www.actabiomedica.it).

High levels of Notch intracellular cleaved domain are associated with stemness and reduced bevacizumab efficacy in patients with advanced colon cancer

δ‑like ligand 4 (DLL4)‑Notch signaling is associated with tumor resistance to anti‑vascular endothelial growth factor (VEGF) therapy. Furthermore, Notch signaling is critical for the maintenance of colon cancer stem cells (CSCs), which are relevant in drug resistance and tumor angiogenesis. CD44 is a transmembrane glycoprotein and is considered a putative marker of CSCs. To assess the association of Notch intracellular cleaved domain (NICD), DLL4 and CD44 expression with the efficacy of anti‑angiogenic drugs, a series of samples derived from patients with advanced colon cancer enrolled in prospective clinical trials were analyzed. Histological samples from 51 primary tumors that originated from patients treated with bevacizumab‑based first‑line chemotherapy were analyzed by immunohistochemistry for NICD, DLL4 and CD44 expression, and CD31 for microvessel count. The expression levels of genes relevant for angiogenesis [angiopoietin (ANGPT)1, ANGPT2, fibroblast growth factor (FGF)1, FGF2, epidermal growth factor, placental growth factor, VEGFA and DLL4] were detected by reverse transcription‑quantitative PCR using RNA extracted from the frozen tissues of four tumors with low and four tumors with high NICD expression. Strong NICD levels were observed in 12/51 (24%) of the patients, whereas 16/51 (31%) of the colon cancer subjects exhibited high CD44 expression. Strong CD44 staining was associated with high NICD levels compared with the CD44 expression levels noted in samples with low NICD levels (67 vs. 20%, P=0.005). No association was observed with regards to the expression levels of NICD, CD44 and the other aforementioned biomarkers. High expression levels of NICD and CD44 predicted reduced progression‑free survival (P<0.001) and overall survival (P=0.002). No significant differences in the expression of angiogenesis‑related genes were detected between low and high NICD‑expressing tumors. In conclusion, NICD and CD44 tissue levels exhibited an association and may be related to a reduced survival rate in patients with advanced colon cancer treated with bevacizumab.

From the beginning to resistance: Study of plasma monitoring and resistance mechanisms in a cohort of patients treated with osimertinib for advanced T790M-positive NSCLC

INTRODUCTION

Analysis of circulating tumor DNA (ctDNA) for the identification of T790M mutation in advanced EGFR-mutated NSCLC patients can replace tissue re-biopsy for resistance characterization and, being non-invasive, may be applied for disease monitoring. We analysed ctDNA during osimertinib treatment to correlate mutational levels with clinical outcome and to predict pattern of resistance.

MATERIALS AND METHODS

Forty patients with advanced NSCLC receiving osimertinib for T790M + disease after previous EGFR-TKI were enrolled in a pilot study to collect plasma at baseline and every 12 weeks until progression. Molecular analysis of ctDNA was performed by ddPCR and Therascreen®. When feasible at progression, tissue re-biopsy and NGS analysis were performed.

RESULTS

Thirty-eight patients had baseline plasma samples suitable for molecular analysis. Patients with low levels of the EGFR activating mutation in ctDNA [< 2200 copies/mL or allele frequency (AF) < 6.1%] showed better progression-free survival (17.8 or 17.8 months vs. 4.3 or 2.7, p = 0.022 or p = 0.018, respectively) and overall survival (23.6 or 23.6 vs. 7.7 or 7.3, p = 0.016 or p = 0.013, respectively) than patients with high levels (≥ 2200 copies/mL or AF ≥ 6.1%). Patients with detectable EGFR mutations in plasma (shedders) presented worse outcome than negative subjects (non-shedders). Low levels of T790M, higher T790M/activating mutation ratio and complete clearance after 2 months were associated with a trend towards better outcome. Tissue re-biopsy at resistance showed 3 patients with EGFR C797S, 1 with MET amplification, 1 with MYC amplification, 1 with PTEN loss, 3 with SCLC transformation.

CONCLUSIONS

The mutational analysis performed on plasma plays a significant role in prognostic stratification, especially for the EGFR activating mutation, since patients with absence or low levels of mutations presented a better outcome to osimertinib. At progression, tissue re-biopsy remains a crucial issue for the identification of resistance mechanisms.

Impact of laterality and mucinous histology on relapse-free and overall survival in a registry-based colon cancer series

Recent data suggest that tumor laterality and mucinous histology may be clinically relevant. We investigated how both variables impact on the prognosis and the response to therapies in a large population-based cohort of cancer patients. Incidence data, clinical and pathological features, and outcome were systematically collected from the Tumor Registry of Parma over the years 2004–2009. Survival data were modeled by multivariable analysis. 1358 patients affected by stage I–IV colon cancer were considered; 661 (49%) had right-sided and 697 (51%) left-sided tumors. 144 (11%) had mucinous (MAC) and 1214 (89%) non-mucinous (NMAC) histology. MACs and NMACs of the right colon showed no difference in stage distribution, whereas left colon MACs were more frequently in an advanced stage (stage IV) (p = 0.008). Stage IV right colon tumors had a poorer overall survival than stage IV left-sided colon cancers (75^th percentile 20 vs 34 months, p < 0.001). At relapse, MACs were less responsive to systemic therapy and had worse survival compared with NMACs regardless of tumor side (7.1 vs 13.1 months, p = 0.018). Right-sided colon cancers had poorer survival compared to left-sided tumors; the effect was mainly attributable to NMACs. At relapse, MACs had unfavorable prognosis regardless of the primary tumor-side.

Potential predictive biomarkers in locally advanced rectal cancer treated with preoperative chemo-radiotherapy

Fluorouracil-based preoperative chemoradiotherapy represents a standard option for the treatment of locally advanced rectal cancer. Randomized clinical trials have shown that fluorouracil concomitant to preoperative radiation enhances tumor shrinkage (with 10% to 15% of the patients showing a complete pathological tumor response) compared with preoperative radiation alone. A high response rate is of clinical importance in rectal cancer, since patients who achieve a complete pathological response may experience improved long-term survival. Adding oxaliplatin to fluorouracil-based preoperative chemoradiotherapy has no effect on response of the primary rectal tumor and single-agent fluoropyrimidine remains the standard chemotherapy in this setting. Despite novel biological insights and therapeutic advances, little is known about potential biological markers able to predict pathological tumor response before treatment and to subsequently impact patients' prognosis. This review focuses on the current available data on main molecular markers and molecular subtypes and the possible upcoming introduction of such analyses in the clinical setting.

Microsatellite instability in colorectal cancer

Microsatellites are short tandem repeat DNA sequences of one to tetra base pairs distributed throughout the human genome, both in coding and non-coding regions. Owing to their repeated structure, microsatellites are particularly prone to replication errors that are normally repaired by the Mismatch Repair (MMR) system. MMR is a very highly conserved cellular process, involving many proteins, resulting in the identification, and subsequent repair of mismatched bases, likely to have arisen during DNA replication, genetic recombination or chemical or physical damage. Proteins within the MMR system include MLH1, PMS2, MSH2, MSH6, MLH3, MSH3, PMS1, and Exo1. Deficient MMR (dMMR) results in a strong mutator phenotype known as microsatellite instability (MSI), characterized by widespread length polymorphisms of microsatellite sequences due to DNA polymerase slippage. MSI is recognized as one of the major carcinogenetic pathways of colorectal cancer (CRC): it represents a molecular hallmark of hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome (LS); moreover it is detected in 15% of sporadic colorectal cancers, more often due to an epigenetic inactivation of MLH1. Identification of MSI CRC is important, as MSI may serve as a screening tool for detecting LS, a prognostic marker for patient outcome, and a predictive marker for response to chemotherapy and to immunotherapy. (www.actabiomedica.it)

Loss of heterozygosity of key tumor suppressor genes in advanced renal cancer patients treated with nivolumab

AIM

We studied the possible clinical significance of loss of heterozygosity (LOH) at key tumor suppressor genes loci in advanced renal cancer patients treated with nivolumab.

METHODS

LOH study was performed on 3p14.2 (FHIT gene); 3p21.3-21.2; 9p21 (BDMF gene); 9p22 (SH3GL2 gene).

RESULTS

Of 12 patients, 8 (67%) had LOH. The most affected gene was FHIT. All five patients with LOH at FHIT locus had good outcome, mean progression free survival of 6.8 months. The patients LOH negative at FHIT locus had mean progression free survival of 4 months, 67% were treatment refractory. Overall, 75% of patients with LOH of at least one gene had benefit; 75% of LOH negative cases were refractory.

CONCLUSION

LOH at key tumor suppressor genes should be further investigated as predictive for immunotherapy.

Primary resistance to osimertinib due to SCLC transformation: Issue of T790M determination on liquid re-biopsy

OBJECTIVES

EGFR T790M mutation is the most common mechanism of resistance to first-/second-generation EGFR tyrosine kinase inhibitors (TKIs) in non-small cell lung cancer (NSCLC) and could be overcome by third-generation EGFR-TKIs, such as osimertinib. Liquid biopsy, a non-invasive technique used to test the presence of the resistant mutation, may help avoiding tissue re-biopsy. However, analysing only circulating-free DNA, information about other less frequent and coexisting resistance mechanisms may remain unrevealed.

MATERIALS AND METHODS

All patients reported in this series participated in the ASTRIS trial, a real world treatment study testing the efficacy of osimertinib (80mg os die) in advanced T790M-positive NSCLC progressed to prior EGFR-TKI. Patients were considered eligible to osimertinib if T790M positive on tissue or plasma samples. In our patients, EGFR molecular testing on blood sample was conducted with digital droplet PCR (ddPCR).

RESULTS

We report our experience of five patients treated with osimertinib after T790M detection on liquid biopsy that presented a disease progression at first tumor assessment mediated by SCLC transformation, as evidenced at tissue re-biopsies. All patients showed low ratio T790M/activating mutation in the blood before osimertinib (lower than 0.03). For three patients, EGFR mutational analysis was T790M-negative when re-assessed by using a less sensitive method (therascreen^®) on the same liquid biopsy sample analysed by ddPCR before osimertinib therapy.

CONCLUSION

Although liquid biopsy is a relevant tool to diagnose T790M presence in NSCLC patients resistant to EGFR-TKI, in case of a low ratio T790M/activating mutation, tissue biopsy should be considered to exclude the presence of SCLC transformation and/or other concomitant resistance mechanisms.

Surgical treatment of multiple sporadic colorectal carcinoma

Aim: Many aspects of the surgical management of multiple sporadic colorectal cancer syndrome, either synchronous and metachronous, remain to be cleared, in particular the prognostic influence of the extent of surgical resection. Method: A retrospective review was performed of patients diagnosed with multiple colorectal cancer from 1982 to May 2010. Clinical and pathologic data were collected and reviewed. Survival analysis was performed. Results: We identified 23 patients with multiple sporadic colorectal cancers, of which 8 had synchronous (SC) and 15 metachronous cancers (MC). Of the MC patients, 2 (13%) had the second cancer within 2 years, 4 (27%) in the time period of 2-5 years and 9 (60%) after 5 years. Twenty-one patients underwent multiple segmental resections; 2 patients underwent subtotal colectomy. The 5-year overall survival rate of SC and MC patients was 100% and 87% (p<0.001) respectively. The 5-year overall survival rate of multiple segmental resection patients and subtotal colectomy was 94% and 75% (p=0.655) respectively. Conclusion: Either synchronous and metachronous MSCRC patients showed good prognosis independently from to the extent of resection. Our results support a less aggressive biological behaviour allowing a more conservative management. Multiple segmental colorectal resections seem appropriate from an oncologic point of view in MSCRC patients. (www.actabiomedica.it)

Correlations between tumor-infiltrating and circulating lymphocyte subpopulations in mRCC patients treated with immune-checkpoint inhibitors

494

Background: In clinical trials with immune-checkpoint inhibitors (CKI), histological features such as tumor-infiltrating lymphocites (TILs) are investigated as potential predictive biomarkers, with the possible limit of an outdated parameter for a typically dynamic element. Methods: This explorative study compared, in metastatic renal cell carcinoma (mRCC) patients, basal pathological data about TILs on diagnostic histological specimens with circulating lymphocyte subpopulations measured before and during therapy with nivolumab, with the primary aim to assess their concordance. Secondarily, with the limit of a small sample size, a possible relation with treatment outcome was explored. Results: Of 11 mRCC patients, 5 had low presence of TILs (L-TILs), 3 moderate amount (M-TILs), and 3 high number (H-TILs). Overall, 8 patients had low intratumoral pathological CD4+/CD8+ ratio (LIPR) ≤ 1 and 3 cases high intratumoral pathological ratio (HIPR) ≥ 2. Of 8 patients with LIPR, only 2 cases matched with low circulating CD4+/CD8+ ratio (LCR) ≤1, whilst 5 cases had high circulating ratio (HCR) ≥ 2 (1 undetermined). All 3 cases with HIPR (≥ 2) conversely had LCR (≤ 1). Unexpectedly, independently from the clinical outcome, circulating CD4+/CD8+ ratio remained unchanged during therapy with CKI in each patient, maintaining the same value after 8 weeks (mean -0.12). The respective percentage values of CD4+ and CD8+ circulating T cells also remained stable during treatment (mean variation 0%); the absolute value of CD4+ was more likely to increase (mean +46.3/mm3); the level of CD8+ tended to slightly decrease (mean -6.5/mm3). No correlation of lymphocyte subpopulations with treatment outcome was found. Conclusions: Of note, this study did not evidence any correspondence between histopathological and circulating findings in terms of T-lymphocyte subpopulations in mRCC patients undergoing treatment with CKI, also suggesting the inconsistency of circulating data in terms of relative variations. Considering the likely high dynamism of TILs, rebiopsy before CKI therapy might be the most reliable way to assess the utility of TILs characterization for predictive purpose.