Hybrid epithelial-mesenchymal status of lung cancer dictates metastatic success through differential interaction with NK cells

BACKGROUND

Epithelial to mesenchymal transition (EMT) endows cancer cells with pro-metastatic properties, which appear most effective when cells enter an intermediate hybrid (H) state, characterized by integrated mesenchymal (M) and epithelial (E) traits. The reasons for this advantage are poorly known and, especially, it is totally unexplored whether the interplay between H-cells and NK cells could have a role. Here we characterize the pro-metastatic mechanics of non-small cell lung cancer (NSCLC) H-cells and their subset of cancer-initiating cells (CICs), dissecting crucial interactions with NK cells.

METHODS

Human lung cancer cell lines and sublines representative of E, M, or H states, assessed by proteomics, were analyzed in vivo for their tumor-forming and disseminating capabilities. Interactions with NK cells were investigated in vitro using migration assays, cytotoxic degranulation assays, and evaluation of CD133+ CICs modulation after coculture, and validated in vivo through NK cell neutralization assays. Correlation between EMT status, NK cell infiltration, and survival data, was evaluated in a cohort of surgically resected NSCLC cases (n=79).

RESULTS

We demonstrated that H-cells, have limited dissemination capability but show the highest potential to initiate metastases in vivo. This property was related to their ability to escape NK cell surveillance. Mechanistically, H-cells expressed low levels of NK-attracting chemokines (CXCL1 and CXCL8), generating poorly infiltrated metastases. Accordingly, proteomics and GO enrichment analysis of E, H, M cell lines showed that the related secretory processes could change during EMT.Furthermore, H-CICs uniquely expressed high levels of the inhibitory ligand B7-H3, which protected H-CIC from NK cell-mediated clearance. In vivo neutralization assays confirmed that, indeed, the pro-metastatic properties of H-cells are poorly controlled by NK cells.Finally, the analysis of patients revealed that detection of hybrid phenotypes associated with low NK infiltration in NSCLC clinical specimens could identify a subset of patients with poor prognosis.

CONCLUSIONS

Our study demonstrates that H-cells play a central role in the metastatic spread in NSCLC. Such pro-metastatic advantage of H-cells is supported by their altered interaction with NK cells and by the critical role of B7-H3 in preserving their H-CIC component, indicating B7-H3 as a potential target in combined NK-based therapies.

Characterization of two transcriptomic subtypes of marker-null large cell carcinoma of the lung suggests different origin and potential new therapeutic perspectives

Pulmonary large cell carcinoma (LCC) is an undifferentiated neoplasm lacking morphological, histochemical, and immunohistochemical features of small cell lung cancer, adenocarcinoma (ADC), or squamous cell carcinoma (SCC). The available molecular information on this rare disease is limited. This study aimed to provide an integrated molecular overview of 16 cases evaluating the mutational asset of 409 genes and the transcriptomic profiles of 20,815 genes. Our data showed that TP53 was the most frequently inactivated gene (15/16; 93.7%) followed by RB1 (5/16; 31.3%) and KEAP1 (4/16; 25%), while CRKL and MYB genes were each amplified in 4/16 (25%) cases and MYC in 3/16 (18.8%) cases; transcriptomic analysis identified two molecular subtypes including a Pure-LCC and an adenocarcinoma like-LCC (ADLike-LCC) characterized by different activated pathways and cell of origin. In the Pure-LCC group, POU2F3 and FOXI1 were distinctive overexpressed markers. A tuft cell-like profile and the enrichment of a replication stress signature, particularly involving ATR, was related to this profile. Differently, the ADLike-LCC were characterized by an alveolar-cell transcriptomic profile and association with AIM2 inflammasome complex signature. In conclusion, our study split the histological marker-null LCC into two different transcriptomic entities, with POU2F3, FOXI1, and AIM2 genes as differential expression markers that might be probed by immunohistochemistry for the differential diagnosis between Pure-LCC and ADLike-LCC. Finally, the identification of several signatures linked to replication stress in Pure-LCC and inflammasome complex in ADLike-LCC could be useful for designing new potential therapeutic approaches for these subtypes.

Clinical impact of mixed pulmonary carcinoma and carcinoid: the driver from their mono-clonal origin

The combination of neuroendocrine/non neuroendocrine lung tumors (CNNELT) mentioned in the last edition of the World Health Organization (WHO) of Thoracic Tumors refers to small cell carcinoma (SCLC) or large cell neuroendocrine carcinoma (LCNEC) mixed with any other non-small cell lung carcinoma (NSCLC). Typical Carcinoid (TC)/Atypical Carcinoid (AC) combined with NSCLC is not included among this category. However, case reports of TC/AC combined with NSCLC have been described. We previously reported 2 cases of lung adenocarcinoma (LUA) mixed with carcinoid sharing mutations in both components supporting the hypothesis of a clonal origin. We extended our analysis to other four cases of mixed NSCLC-carcinoid by performing targeted-DNA and RNA-based NGS analysis in both primary and their paired lymph nodes metastasis. In all cases, LUA and AC components shared at least 1 common mutation (KRAS driver mutation p.Gly12Val in cases 1 and 3, AKAP13-RET fusion in case 2, and missense KRAS driver mutation p.Gly12Ala in case 4, reinforcing the hypothesis of a clonal origin. Moreover, the same mutation was detected in the metastasis constituted only by AC (cases 2 and 4). Although it is a rare malignancy in the lung, mixed LUA and TC/AC could be included among the histotypes for which a deep molecular characterization of both components is needed to identify the presence of potential druggable genetic alterations.

NUT carcinoma of the submandibular gland: A case report

BACKGROUND

NUT carcinoma (NUTc) is a rare and aggressive malignant epithelial tumor characterized by rearrangement of the NUT gene on chromosome 15q14.

METHODS

In this article, we present the fifth case worldwide of a young woman affected by a NUTc arising from a submandibular gland, presenting as a rapidly evolving mass. She underwent a right scialoadenectomy and received the initial diagnosis of high-grade mucoepidermoid carcinoma. Due to evidence of local recurrence at magnetic resonance imaging 1 month later, a subsequent right radical neck dissection was performed. The patient then sought a second opinion at our cancer center and finally received the correct diagnosis of NUT carcinoma. Given the well-known aggressive behavior of this neoplasm, as well as clinical and radiological features, she underwent adjuvant chemo-radiation (intensity-modulated radiotherapy + concurrent chemotherapy with cisplatin).

RESULTS

After a disease-free interval of 2.6 months, a widespread metastatic disease led to rapid deterioration of performance status and patient death in a few weeks after metastatic onset.

CONCLUSIONS

We presented a case of NUTc arising from salivary gland aiming to improve the knowledge of this rare malignancy. First, we pointed out that in the setting of rare tumors like salivary gland cancers, the diagnosis should be obtained by expert pathologists, and patients should be referred to tertiary cancer centers for their clinical management. Second, molecular profiling may help to identify possible druggable targets that may be exploited to treat patients suffering from this aggressive malignancy. Sharing the molecular data provided in this case will be useful for further research.

FAP expression in alpha cells of Langherhans insulae-implications for FAPI radiopharmaceuticals' use

PURPOSE

Radiopharmaceuticals targeting fibroblast activation protein (FAP) alpha are increasingly studied for diagnostic and therapeutic applications. We discovered FAP expression at immunohistochemistry (IHC) in the alpha cells of the Langerhans insulae of few patients. Therefore, we planned an investigation aimed at describing FAP expression in the pancreas and discussing the implications for radioligand applications.

METHODS

We retrospectively included 40 patients from 2 institutions (20 pts each) according to the following inclusion/exclusion criteria: (i) pathology proven pancreatic ductal adenocarcinoma and neuroendocrine tumors (NET), 10 pts per each group at each center; (ii) and availability of paraffin-embedded tissue; and (iii) clinical-pathological records. We performed IHC analysis and applied a semiquantitative visual scoring system (0, negative staining; 1, present in less than 30%; 2, present in more than 30% of the area). FAP expression was assessed according to histology-NET (n = 20) vs ductal adenocarcinoma (n = 20)-and to previous treatments within the adenocarcinoma group. The local ethics committee approved the study (No. INT 21/16, 28 January 2016).

RESULTS

The population consisted of 24 males and 16 females, with a median age of 68 and a range of 14-84 years; 8/20 adenocarcinoma patients received chemotherapy. In all the Langerhans insulae (40/40), pancreatic alpha cells were found to express FAP, with a score of 2. No difference was found among NET (20/20) and adenocarcinoma (20/20), nor according to neoadjuvant chemotherapy in the adenocarcinoma cohort (received or not received).

CONCLUSION

Pancreatic Langerhans islet alpha cells normally express FAP. This is not expected to influence the diagnostic accuracy of FAP-targeting tracers. In the therapeutic setting, our results suggest the need to better elucidate FAPI radioligands' effects on the Langerhans insulae function.

Transcriptome analysis of primary sporadic neuroendocrine tumours of the intestine identified three different molecular subgroups

BACKGROUND

Intestinal neuroendocrine tumours (I-NETs) represent a non-negligible entity among intestinal neoplasms, with metastatic spreading usually present at the time of diagnosis. In this context, effective molecular actionable targets are still lacking. Through transcriptome analysis, we aim at refining the molecular taxonomy of I-NETs, also providing insights towards the identification of new therapeutic vulnerabilities.

MATERIALS AND METHODS

A retrospective series of 38 primary sporadic, surgically-resected I-NETs were assessed for transcriptome profiling of 20,815 genes.

RESULTS

Transcriptome analysis detected 643 highly expressed genes. Unsupervised hierarchical clustering, differential expression analysis and gene set enriched analysis identified three different tumour clusters (CL): CL-A, CL-B, CL-C. CL-A showed the overexpression of ARGFX, BIRC8, NANOS2, and SSTR4 genes. Its most characterizing signatures were those related to cell-junctions, and activation of mTOR and WNT pathway. CL-A was also enriched in T CD8 + lymphocytes. CL-B showed the overexpression of PCSK1, QPCT, ST18, and TPH1 genes. Its most characterizing signatures were those related to adipogenesis, neuroendocrine metabolism, and splice site machinery-related processes. CL-B was also enriched in T CD4 + lymphocytes. CL-C showed the overexpression of ALB, ANG, ARG1, and HP genes. Its most characterizing signatures were complement/coagulation and xenobiotic metabolism. CL-C was also enriched in M1/2 macrophages. These CL-based differences may have therapeutic implications in refining the management of I-NET patients. At last, we described a specific gene-set for differentiating I-NET from pancreatic NET.

DISCUSSION

Our data represent an additional step for refining the molecular taxonomy of I-NET, identifying novel transcriptome subgroups with different biology and therapeutic opportunities.

Digestive MiNENs: Could histological classification and molecular characterization drive clinical outcome and therapeutic approach?

Mixed neuroendocrine-non-neuroendocrine neoplasms (MiNENs) are epithelial neoplasms in which neuroendocrine and non-neuroendocrine discrete components are combined, each of which constitutes ≥ 30% of the neoplasm. The finding of an additional neuroendocrine component seems to characterize the tumor's biological behavior. Few studies have proved MiNENs histogenetic and molecular characterization, and the development of molecular markers for more accurate classification of MiNENs represents a clinical need. However, a common origin of the neuroendocrine and non-neuroendocrine components from a pluripotent cancer stem cell could be suggested. The optimal clinical management of MiNENS is largely unknown. Whenever feasible, curative-intent resection should be performed for localized disease; in advanced disease, the treatment should be targeted to the component responsible for the metastatic spreading. This paper provides a revision of the current knowledge on MiNENs, focusing on available evidence about their molecular characterization to suggest a prognostic stratification of these rare forms.

Enantioselective Strategies for The Synthesis of N-N Atropisomers

Axially chiral compounds have been always considered a laboratory curiosity with rare prospects of being applied in asymmetric synthesis. Things have changed very quickly in the last twenty years when it was understood the important role and the enormous impact that these compounds have in medicinal, biological and material chemistry. The asymmetric synthesis of atropisomers became a rapidly expanding field and recent reports on the development of N-N atropisomers strongly prove how this research field is a hot topic open to new challenges and frontiers of asymmetric synthesis. This review focuses on the recent advances in the enantioselective synthesis of N-N atropisomers highlighting the strategies and breakthroughs to obtain this novel and stimulating atropisomeric framework.

Impact of Microscopically Positive (≤1 mm) Distal Margins on Disease Recurrence in Rectal Cancer Treated by Neoadjuvant Chemoradiotherapy

BACKGROUND

The adequate distal resection margin is still controversial in rectal cancer treated by neoadjuvant chemoradiotherapy (nCRT). The aim of this study was to assess the impact of a distal margin of ≤1 mm on locoregional recurrence-free survival (LRRFS).

METHODS

Among 255 patients treated with nCRT and surgery at the National Cancer Institute of Milan, 83 (32.5%) had a distal margin of ≤1 mm and 172 (67.5%) had a distal margin of >1 mm. Survival analyses were performed to assess the impact of distal margin on 5-year LRRFS, as well as Cox survival analysis. The role of distal margin on survival was analyzed according to different tumor regression grades (TRGs).

RESULTS

The overall 5-year LRRFS rate was 77.6% with a distal margin of ≤1 mm vs. 88.3% with a distal margin of >1 mm (Log-rank p = 0.09). Only stage ypT4 was an independent predictor of worse LRRFS (HR 15.14, p = 0.026). The 5-year LRRFS was significantly lower in TRG3-5 patients with a distal margin of ≤1 mm compared to those with a distal margin of >1 mm (68.5% vs. 84.2%, p = 0.027), while no difference was observed in case of TRG1-2 (p = 0.77).

CONCLUSIONS

Low-responder rectal cancers after nCRT still require a distal margin of >1 mm to reduce the high likelihood of local relapse.

Ascl1 and OTP tumour expressions are associated with disease-free survival in lung atypical carcinoids

According to World Health Organization guidelines, atypical carcinoids (ACs) are well-differentiated lung neuroendocrine tumours with 2-10 mitoses/2 mm² and/or foci of necrosis (usually punctate). Besides morphological criteria, no further tools in predicting AC clinical outcomes are proposed. The aim of this work was to identify novel factors able to predict AC disease aggressiveness and progression. METHODS AND RESULTS: Three hundred-seventy lung carcinoids were collected and centrally reviewed by two expert pathologists. Morphology and immunohistochemical markers (Ki-67, TTF-1, CD44, OTP, SSTR2A, Ascl1, p53, and Rb1) were studied and correlated with disease-free survival (DFS) and overall survival (OS). Fifty-eight of 370 tumours were defined as AC. Survival analysis showed that patients with Ascl1 + ACs and those with OTP-ACs had a significantly worse DFS than patients with Ascl1-ACs and OTP + ACs, respectively. Combining Ascl1 and OTP expressions, groups were formed reflecting the aggressiveness of disease (P = 0.0005). Ki-67 ≥10% patients had a significantly worse DFS than patients with Ki-67 <10%. At multivariable analysis, Ascl1 (present versus absent, hazard ratio [HR] = 3.42, 95% confidence interval [CI] 1.35-8.65, P = 0.009) and OTP (present versus absent, HR = 0.26, 95% CI 0.10-0.68, P = 0.006) were independently associated with DFS. The prognosis of patients with Ki-67 ≥10% tended to be worse compared to that with Ki-67 <10%. On the contrary, OTP (present versus absent, HR = 0.28, 95% CI 0.09-0.89, P = 0.03), tumour stage (III-IV versus I-II, HR = 4.25, 95% CI 1.42-12.73, P = 0.01) and increasing age (10-year increase, HR = 1.67, 95% CI 1.04-2.68, P = 0.03) were independently associated with OS. CONCLUSION: This retrospective analysis of lung ACs showed that Ascl1 and OTP could be the main prognostic drivers of postoperative recurrence.

Lung carcinoid tumours: histology and Ki-67, the eternal rivalry

WHO classification of Thoracic Tumours defines lung carcinoid tumours (LCTs) as well-differentiated neuroendocrine neoplasms (NENs) classified in low grade typical (TC) and intermediate grade atypical carcinoids (AC). Limited data exist concerning protein expression and morphologic factors able to predict disease aggressiveness. Though Ki-67 has proved to be a powerful diagnostic and prognostic factor for Gastro-entero-pancreatic NENs, its role in lung NENs is still debated. A retrospective series of 370 LCT from two oncology centers was centrally reviewed. Morphology and immunohistochemical markers (Ki-67, TTF-1, CD44, OTP, SSTR-2A, Ascl1, and p53) were studied and correlated with Overall Survival (OS), Cancer-specific survival (CSS) and Disease-free survival (DFS). Carcinoid histology was confirmed in 355 patients: 297 (83.7%) TC and 58 (16.3%) AC. Ki-67 at 3% was the best value in predicting DFS. Ki-67 ≥ 3% tumours were significantly associated with AC histology, stage III-IV, smoking, vascular invasion, tumour spread through air spaces OTP negativity, and TTF-1, Ascl1 and p53 positivity. After adjustment for center and period of diagnosis, both Ki-67 (≥3 versus <3) and histology (AC versus TC) alone significantly added prognostic information to OS and CSS multivariable model with age, stage and OTP; addition of both variables did not provide further prognostic information. Conversely, an improved significance of the DFS prediction model at multivariate analysis was seen by adding Ki-67 (≥3 versus <3, P adj = 0.01) to TC and AC histological distinction, age, lymph node involvement, residual tumour and OTP. Ki-67 ≥ 3% plays a potentially pivotal role in LCT prognosis, irrespective of histological grade.

Adamantinoma-like Ewing sarcoma of the salivary glands: a case report and systematic literature review

Adamantinoma-like Ewing sarcoma (ALES) of the salivary glands is an exceedingly rare malignancy defined by the t(11,22) EWSR1::FLI1 fusion, with complex epithelial differentiation. To identify features that can allow for better recognition of this disease entity, we reviewed all published reports of molecularly confirmed ALES of the salivary glands and explored epidemiological, clinical, radiological, pathological, and therapeutic characteristics of a population of 21 patients including a single newly reported patient from our group. We searched the English-language literature indexed in PubMed, Medline, Scopus, and Web of Science using the keyword 'Adamantinoma-like Ewing sarcoma' published up to June 2022. The median age at diagnosis was 46 years, and a slight female sex predilection was observed. Most tumors originated in the parotid gland (86%) and presented as a painless palpable mass with a median diameter of 3.6 cm. Metastatic dissemination was reported only in one patient (5%), and after a median follow-up of 13 months the 1-year overall survival rate was 92%. Salivary gland ALES were frequently misdiagnosed at presentation (62% of cases) and were pathologically characterized by the presence of highly monomorphic small round blue cells with infiltrative pattern and positive immunostaining for CD99 and high- and low-molecular weight cytokeratins. Epidemiological and clinical features of salivary gland ALES raise questions on the incorporation of this malignancy in the Ewing sarcoma family tumor group.

Role of Cinchona Alkaloids in the Enantio- and Diastereoselective Synthesis of Axially Chiral Compounds

Asymmetric synthesis using organic catalysts has evolved since it was first realized and defined. Nowadays, it can be considered a valid alternative to transition metal catalysis for synthesizing chiral molecules. According to the literature, the number of asymmetric organocatalytic processes associated with atropisomer synthesis has rapidly increased over the past 10 years because organocatalysis addresses the challenges posed by the most widespread strategies used for preparing axially chiral molecules with satisfactory results.These strategies, useful to prepare a wide range of C-C, C-heteroatom, and N-N atropisomers, vary from kinetic resolution to direct arylation, desymmetrization, and central-to-axial chirality conversion. In this field, our contribution focuses on determining novel methods for synthesizing atropisomers, during which, in most cases, the construction of one or more stereogenic centers other than the stereogenic axis occurred. To efficiently address this challenge, we exploited the ability of catalysts based on a cinchona alkaloid scaffold to realize enantioselective organic transformations. Desymmetrization of N-(2-tert-butylphenyl) maleimides was one of the first strategies that we pursued for preparing C-N atropisomers. The main principle is based on the presence of a rotationally hindered C-N single bond owing to the presence of a large tert-butyl group. Following the peculiar reactivity of this type of substrate as a powerful electrophile and dienophile, we realized several transformations.First, we investigated the vinylogous Michael addition of 3-substituted cyclohexenones, where a stereogenic axis and two contiguous stereocenters were concomitantly and remotely formed and stereocontrolled using a primary amine catalyst. Subsequently, we realized desymmetrization via an organocatalytic Diels-Alder reaction of activated unsaturated ketones that enabled highly atropselective transformation with efficient diastereoselectivity, thereby simultaneously controlling four stereogenic elements. Employing chiral organic bases allowed us to realize efficient desymmetrizations using carbon nucleophiles, such as 1,3-dicarbonyl compounds, cyanoacetates, and oxindoles. These reactions, performed with different types of catalysts, highlighted the versatility of organocatalysis as a powerful strategy for atropselective desymmetrization of pro-axially chiral maleimides.Hereafter, we studied the Friedel-Crafts alkylation of naphthols with indenones, a powerful method for enantioselective synthesis of conformationally restricted diastereoisomeric indanones. We realized the first axially chiral selective Knoevenagel condensation using cinchona alkaloid primary amine as the catalyst. This reaction provided a powerful method to access enantioenriched olefins containing the oxindole core. Subsequently, we initiated an intense program for the computational investigation of the reaction mechanism of our atropselective processes. An understanding of the catalytic activity for vinylogous atropselective desymmetrization as well as of the role played by the acidic cocatalyst used for the experimental work was achieved.Recently, we have garnered interest in the novel frontiers of atropselective synthesis. As observed in recent publications, there is considerable interest in the development of methods for preparing N-N atropisomers, an emerging topic in the field of atropselective synthesis. We focused on the synthesis of hydrazide atropisomers by developing a one-pot sequential catalysis protocol based on two sequential organocatalytic reactions that provided high stereocontrol of two contiguous stereogenic elements.

Prognostic Factors across Poorly Differentiated Neuroendocrine Neoplasms: A Pooled Analysis

INTRODUCTION

Poorly differentiated neuroendocrine carcinomas (NECs) are characterized by aggressive clinical course and poor prognosis. No reliable prognostic markers have been validated to date; thus, the definition of a specific NEC prognostic algorithm represents a clinical need. This study aimed to analyze a large NEC case series to validate the specific prognostic factors identified in previous studies on gastro-entero-pancreatic and lung NECs and to assess if further prognostic parameters can be isolated.

METHODS

A pooled analysis of four NEC retrospective studies was performed to evaluate the prognostic role of Ki-67 cut-off, the overall survival (OS) according to primary cancer site, and further prognostic parameters using multivariable Cox proportional hazards model and machine learning random survival forest (RSF).

RESULTS

422 NECs were analyzed. The most represented tumor site was the colorectum (n = 156, 37%), followed by the lungs (n = 111, 26%), gastroesophageal site (n = 83, 20%; 66 gastric, 79%) and pancreas (n = 42, 10%). The Ki-67 index was the most relevant predictor, followed by morphology (pure or mixed/combined NECs), stage, and site. The predicted RSF response for survival at 1, 2, or 3 years showed decreasing survival with increasing Ki-67, pure NEC morphology, stage III-IV, and colorectal NEC disease. Patients with Ki-67 <55% and mixed/combined morphology had better survival than those with pure morphology. Morphology pure or mixed/combined became irrelevant in NEC survival when Ki-67 was ≥55%. The prognosis of metastatic patients who did not receive any treatment tended to be worse compared to that of the treated group. The prognostic impact of Rb1 immunolabeling appears to be limited when multiple risk factors are simultaneously assessed.

CONCLUSION

The most effective parameters to predict OS for NEC patients could be Ki-67, pure or mixed/combined morphology, stage, and site.

Synthesis of Atropisomeric Hydrazides by One-Pot Sequential Enantio- and Diastereoselective Catalysis

The first catalytic enantioselective and diastereoselective synthesis of atropisomeric hydrazides was achieved using a sequential catalysis protocol. This strategy is based on a one-pot sequence of two organocatalytic cycles featuring the enamine amination of branched aldehydes followed by nitrogen alkylation under phase-transfer conditions. The resulting axially chiral hydrazides were obtained directly from commercially available reagents in high yields and with good stereocontrol. The permutation of organocatalysts allowed easy access to all stereoisomers, enabling a stereodivergent approach to enantioenriched atropisomeric hydrazides.

Establishment of 6 pediatric rhabdomyosarcoma patient’s derived xenograft models closely recapitulating patients’ tumor characteristics

Introduction:

The prognosis for patients with metastatic and recurrent pediatric rhabdomyosarcoma (RMS) remains poor. The availability of preclinical models is essential to identify promising treatments We established a series of pediatric RMS patient derived xenografts (PDXs), all faithfully mirroring primary tumor characteristics and representing a unique tool for clarifying the biological processes underlying RMS progression and relapse.

Methods:

Fresh tumor samples from 12 RMS patients were implanted subcutaneously in both flanks of immunocompromised mice. PDXs were considered as grafted after accomplishing three passages in mice. Characterization of tumor tissues and models was performed by comparing both morphology and immunoistochemical and fluorescence in situ hybridization (FISH) characteristics.

Results:

Six PDXs were established, with a successful take rate of 50%. All models closely mirrored parental tumor characteristics. An increased grafting rate for tumors derived from patients with worse outcome (p = 0.006) was detected. For 50% PDXs grafting occurred when the corresponding patient was still alive.

Conclusion:

Our findings increase the number of available RMS PDX models and strengthen the role of PDXs as useful preclinical tools for patients with unmet medical needs and to develop personalized therapies.

Potential of the Stromal Matricellular Protein Periostin as a Biomarker to Improve Risk Assessment in Prostate Cancer

Prostate cancer (PCa) ranges from indolent to aggressive tumors that may rapidly progress and metastasize. The switch to aggressive PCa is fostered by reactive stroma infiltrating tumor foci. Therefore, reactive stroma-based biomarkers may potentially improve the early detection of aggressive PCa, ameliorating disease classification. Gene expression profiles of PCa reactive fibroblasts highlighted the up-regulation of genes related to stroma deposition, including periostin and sparc. Here, the potential of periostin as a stromal biomarker has been investigated on PCa prostatectomies by immunohistochemistry. Moreover, circulating levels of periostin and sparc have been assessed in a low-risk PCa patient cohort enrolled in active surveillance (AS) by ELISA. We found that periostin is mainly expressed in the peritumoral stroma of prostatectomies, and its stromal expression correlates with PCa grade and aggressive disease features, such as the cribriform growth. Moreover, stromal periostin staining is associated with a shorter biochemical recurrence-free survival of PCa patients. Interestingly, the integration of periostin and sparc circulating levels into a model based on standard clinico-pathological variables improves its performance in predicting disease reclassification of AS patients. In this study, we provide the first evidence that circulating molecular biomarkers of PCa stroma may refine risk assessment and predict the reclassification of AS patients.

Abstract 1539: LKB1 down-modulation by miR-17 biologically and clinically mirrors LKB1-mutated NSCLC

Introduction: In non-small cell lung cancer (NSCLC) LKB1 mutations combined with KRAS hyperactivation define a poor responsive, aggressive and disseminating phenotype. We recently unveiled the vulnerability of KRAS/LKB1 co-mutated (KL) patient-derived xenografts (PDXs) to metabolic stress-based treatments, and a clinical trial to test the efficacy of metformin and fasting-mimicking diet on KL NSCLC is currently ongoing in our Institute. Besides inactivating mutations, LKB1 functionality may be impaired by post-translation regulation. Because miR-17 is a potential epigenetic regulator of LKB1,we hypothesized that wild-type LKB1 (LKB1WT) NSCLC with high miR-17 expression may biologically and clinically mirror LKB1 mutated tumors.

Methods: NSCLC cell lines with different combinations of KRAS mutation and LKB1 deletion were selected, together with a panel of PDXs with high (LKB1WT/miR-17 high) or low (LKB1WT/miR-17 low) miR-17 expression. Taking advantage of series of NSCLC patients and PDXs, we retrospectively evaluated LKB1 and miR-17 expression levels in tumor tissue specimens. In addition, the TCGA dataset was interrogated for miR-17 expression and potential correlation with lung cancer clinical features.

Results: Direct targeting of miR-17 to LKB1 3’UTR was confirmed by luciferase reporter assay. We found that miR-17 overexpression in LKB1WT cell lines functionally impaired the LKB1/AMPK pathway, and prompted apoptotic response to metformin. Of note, LKB1WT/miR-17 high PDXs tumor cells showed a similar behavior upon metformin treatment. A retrospective analysis in patients with NSCLC revealed an inverse correlation between miR-17 and LKB1 expression, and highlighted a prognostic role of miR-17 expression in LKB1WT patients, further confirmed by TCGA data analysis.

Conclusions: We validated miR-17 as epigenetic regulator of LKB1 expression in NSCLC tumors. We propose a miR-17 expression score potentially exploitable to discriminate LKB1WT NSCLC patients with impaired LKB1 expression and poor outcome, eligible for energy-stress-based treatments.

Citation Format: Cristina Borzi, Monica Ganzinelli, Elisa Caiola, Marika Colombo, Giovanni Centonze, Mattia Boeri, Laura Caleca, Ugo Pastorino, Mirko Marabese, Massimo Milione, Massimo Broggini, Marina C. Garassino, Gabriella Sozzi, Massimo Moro. LKB1 down-modulation by miR-17 biologically and clinically mirrors LKB1-mutated NSCLC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1539.

Abstract 962: A hybrid epithelial-mesenchymal phenotype identifies lung cancer cells with high metastatic potential due to increased stemness properties and escape from NK immunosurveillance

Introduction: Epithelial to mesenchymal transition (EMT) is essential for cancer dissemination but its role in overt metastasis establishment remains an open issue. Multiple EMT states and great phenotypic plasticity have also been described, indicating the need for in-depth characterization of biological properties associated with different EMT phenotypes. The so-called hybrid phenotype, characterized by presence of both mesenchymal and epithelial markers, might in fact identify cancer cells with enhanced metastatic propensity.

Materials and Methods: To assess the metastatic potential of different EMT phenotypes, we exploited two lung cancer cell lines with different properties (A549/epithelial and LT73/hybrid) and generated their respective sublines through four sequential rounds of in vitro migration assay (named M4). TGFβ treatment was also used to induce EMT. With a previously validated score based on the ratio between expression of epithelial (CDH1) or mesenchymal genes (SNAI2), cells were classified as: epithelial (A549)&gt;hybrid (A549-M4, LT73)&gt;mesenchymal (LT73-M4, A549-TGFβ). The disseminating/metastatic properties of the different lines were tested in vivo by subcutaneous and tail-vein injections in SCID mice. Interaction with NK cells (NKs), known to specifically target EMT cancer cells, was also assessed.

Results and Discussion: Compared to parental cells, M4 cells showed up-regulation of EMT-associated genes, expansion of the subset of CD133+ lung cancer stem cells (CSC) and displayed in vivo higher ability to disseminate from primary tumors to murine lungs (2-fold change, p=0.004). However, hybrid cells (LT73 and A549-M4) showed an increased ability to generate overt lung metastases in experimental metastasis assays compared to either epithelial (A549) or mesenchymal cells (LT73-M4 and A549-TGFβ). The higher metastatic ability of hybrid cells was correlated with CSCs expansion and reduced NKs infiltration to the metastatic lungs. Expression of IL-8, a cytokine involved in NKs recruitment, was decreased in hybrid cells and they were less prone to chemoattract NKs in vitro compared to both epithelial and mesenchymal cells. Finally, in vivo prevention of NKs recruitment to the lungs using a neutralizing antibody, massively increased metastasis formation and expansion of CSCs in mice injected i.v. with mesenchymal A549-TGFβ (p=0.0006), but had limited effects in groups injected with both epithelial A549 and hybrid A549-M4.

Conclusions: Our data indicate that the hybrid phenotype correlates with the highest metastatic potential related to efficient cancer cell dissemination, increased induction of stemness features and ability to avoid NKs recruitment. Conversely, fully mesenchymal cells show limited metastatic potential, possibly due the control exerted by NKs on their CSC subsets.

Citation Format: Giulia Bertolini, Monica Parodi, Massimo Milione, Fabio Murianni, Giovanni Centonze, Giulia Taiè, Gabriella Sozzi, Massimo Vitale, Luca Roz. A hybrid epithelial-mesenchymal phenotype identifies lung cancer cells with high metastatic potential due to increased stemness properties and escape from NK immunosurveillance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 962.

Colorectal medullary carcinoma: heterogeneous presentations of a rare clinico-pathological entity. Report of two cases

Colorectal medullary carcinoma (CMC) is a rare subset of minimally differentiated carcinomas. CMC tend to be right-sided and present at an advanced stage. Despite this, distant metastases are rare at presentation. The liver and the regional lymph nodes represent the most common sites of metastases. Most of the time, CMCs exhibit mismatch repair deficiency and a strong association with high-level microsatellite instability. There is no conspicuous data regarding treatment strategies and short-term outcomes. CMC is supposed to be related to better prognosis compared to poorly-differentiated and undifferentiated colonic adenocarcinomas, but reports are controversial.This lesion, with heterogeneous presentations and unclear prognostic significance, may be unfamiliar to histopathologists and can lead to diagnostic uncertainty and overtreatments.Our aim is to renew the attention to this rare histological subtype through the report of two cases.

BRAF-mutated colorectal adenocarcinomas: pathological heterogeneity and clinical implications

Advances in molecular biology have markedly increased our understanding of the heterogeneous molecular landscape of colorectal cancer (CRC). Up to 15% of CRCs harbor the BRAF p.V600E somatic mutation (BRAFmt), a well-established negative prognostic marker in patients with metastatic CRC (mCRC). The BEACON CRC trial set a new standard of care in patients with progressive BRAFmt cancers, consisting of the combination of encorafenib and cetuximab. On these bases, BRAF mutational testing is now recommended in patients with mCRC. However, efforts are needed to further stratify patients carrying this mutation. Here, we discuss the heterogeneous pathologic and molecular landscape of BRAFmt CRCs, focusing on the promises and pitfalls of molecular diagnostics, on novel biomarkers to improve patients' stratification and on the current diagnostic scenario for CRC. We believe that a better stratification based on histopathological features and novel molecular biomarkers should be performed to optimize patient management and therapeutic decision-making.

MiR-486-5p Targets CD133+ Lung Cancer Stem Cells through the p85/AKT Pathway

Despite improvements in therapies and screening strategies, lung cancer prognosis still remains dismal, especially for metastatic tumors. Cancer stem cells (CSCs) are endowed with properties such as chemoresistance, dissemination, and stem-like features, that make them one of the main causes of the poor survival rate of lung cancer patients. MicroRNAs (miRNAs), small molecules regulating gene expression, have a role in lung cancer development and progression. In particular, miR-486-5p is an onco-suppressor miRNA found to be down-modulated in the tumor tissue of lung cancer patients. In this study, we investigate the role of this miRNA in CD133+ lung CSCs and evaluate the therapeutic efficacy of coated cationic lipid-nanoparticles entrapping the miR-486-5p miRNA mimic (CCL-486) using lung cancer patient-derived xenograft (PDX) models. In vitro, miR-486-5p overexpression impaired the PI3K/Akt pathway and decreased lung cancer cell viability. Moreover, miR-486-5p overexpression induced apoptosis also in CD133+ CSCs, thus affecting the in vivo tumor-initiating properties of these cells. Finally, we demonstrated that in vivo CCL-486 treatment decreased CD133+ percentage and inhibited tumor growth in PDX models. In conclusion, we provided insights on the efficacy of a novel miRNA-based compound to hit CD133+ lung CSCs, setting the basis for new combined therapeutic strategies.

Intratumor Microbiome in Neuroendocrine Neoplasms: A New Partner of Tumor Microenvironment? A Pilot Study

Neuroendocrine neoplasms (NENs) are rare neoplasms with heterogeneous clinical behavior. Alteration in human microbiota was reported in association with carcinogenesis in different solid tumors. However, few studies addressed the role of microbiota in NEN. We here aimed at evaluating the presence of bacterial infiltration in neuroendocrine tumoral tissue. To assess the presence of bacteria, 20 specimens from pancreatic NEN (pan-NEN) and 20 from intestinal NEN (I-NEN) were evaluated through Fluorescent In situ Hybridization and confocal microscopy. Demographic data, pre-operative investigations, operative findings, pathological diagnosis, follow-up, and survival data were evaluated. Among I-NEN, bacteria were detected in 15/20 (75%) specimens, with high variability in microbial distribution. In eight patients, a high infiltration of microorganisms was observed. Among pan-NEN, 18/20 (90%) showed microorganisms’ infiltration, with a homogeneous microbial distribution. Bacterial localization in pan-NEN was observed in the proximity of blood vessels. A higher bacterial infiltration in the tumoral specimen as compared with non-tumoral tissue was reported in 10/20 pan-NEN (50%). No significant differences were observed in mean bacterial count according to age, sex, ki67%, site, tumor stage. Mean bacterial count did not result to be a predictor of disease-specific survival. This preliminary study demonstrates the presence of a significant microbiota in the NEN microenvironment. Further research is needed to investigate the potential etiological or clinical role of microbiota in NEN.

Biomarker Landscape in Neuroendocrine Tumors With High-Grade Features: Current Knowledge and Future Perspective

Neuroendocrine tumors (NETs) are classified based on morphology and are graded based on their proliferation rate as either well-differentiated low-grade (G1) to intermediate (G2–G3) or poorly differentiated high-grade neuroendocrine carcinomas (NEC G3). Recently, in gastroenteropancreatic (GEP) NETs, a new subgroup of well-differentiated high-grade tumors (NET G3) has been divided from NEC by WHO due to its different clinical–pathologic features. Although several mutational analyses have been performed, a molecular classification of NET is an unmet need in particular for G3, which tends to be more aggressive and have less benefit to the available therapies. Specifically, new possible prognostic and, above all, predictive factors are highly awaited, giving the basis for new treatments. Alteration of KRAS, TP53, and RB1 is mainly reported, but also druggable alterations, including BRAF and high microsatellite instability (MSI-H), have been documented in subsets of patients. In addition, PD-L1 demonstrated to be highly expressed in G3 NETs, probably becoming a new biomarker for G3 neuroendocrine neoplasm (NEN) discrimination and a predictive one for immunotherapy response. In this review, we describe the current knowledge available on a high-grade NET molecular landscape with a specific focus on those harboring potentially therapeutic targets in the advanced setting.

Integrative molecular analysis of combined small-cell lung carcinomas identifies major subtypes with different therapeutic opportunities

BACKGROUND

Combined small-cell lung cancer (C-SCLC) is composed of SCLC admixed with a non-small-cell cancer component. They currently receive the same treatment as SCLC. The recent evidence that SCLC may belong to either of two lineages, neuroendocrine (NE) or non-NE, with different vulnerability to specific cell death pathways such as ferroptosis, opens new therapeutic opportunities also for C-SCLC.

MATERIALS AND METHODS

Thirteen C-SCLCs, including five with adenocarcinoma (CoADC), five with large-cell neuroendocrine carcinoma (CoLCNEC) and three with squamous cell carcinoma (CoSQC) components, were assessed for alterations in 409 genes and transcriptomic profiling of 20 815 genes.

RESULTS

All 13 cases harbored TP53 (12 cases) and/or RB1 (7 cases) inactivation, which was accompanied by mutated KRAS in 4 and PTEN in 3 cases. Potentially targetable alterations included two KRAS G12C, two PIK3CA and one EGFR mutations. Comparison of C-SCLC transcriptomes with those of 57 pure histology lung cancers (17 ADCs, 20 SQCs, 11 LCNECs, 9 SCLCs) showed that CoLCNEC and CoADC constituted a standalone group of NE tumors, while CoSQC transcriptional setup was overlapping that of pure SQC. Using transcriptional signatures of NE versus non-NE SCLC as classifier, CoLCNEC was clearly NE while CoSQC was strongly non-NE and CoADC exhibited a heterogeneous phenotype. Similarly, using ferroptosis sensitivity/resistance markers, CoSQC was classified as sensitive (as expected for non-NE), CoLCNEC as resistant (as expected for NE) and CoADC showed a heterogeneous pattern.

CONCLUSIONS

These data support routine molecular profiling of C-SCLC to search for targetable driver alterations and to precisely classify them according to therapeutically relevant subgroups (e.g. NE versus non-NE).

Identification of Targetable Liabilities in the Dynamic Metabolic Profile of EGFR-Mutant Lung Adenocarcinoma: Thinking beyond Genomics for Overcoming EGFR TKI Resistance

The use of epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) as first-line treatment in patients with lung adenocarcinoma (LUAD) harboring EGFR-activating mutations has resulted in a dramatic improvement in the management of the disease. However, the long-term clinical benefit is inevitably compromised by multiple resistance mechanisms. Accumulating evidence suggests that metabolic landscape remodeling is one of the mechanisms that EGFR-mutant LUAD cells activate, thus acquiring higher plasticity, tolerating EGFR TKI-mediated cytotoxic stress, and sustaining their oncogenic phenotype. Several metabolic pathways are upregulated in EGFR TKI-resistant models modulating the levels of numerous metabolites such as lipids, carbohydrates, and metabolic enzymes which have been suggested as potential mediators of resistance to EGFR TKIs. Moreover, metabolites have been shown to carry signals and stimulate oncogenic pathways and tumor microenvironment (TME) components such as fibroblasts, facilitating resistance to EGFR TKIs in various ways. Interestingly, metabolic signatures could function as predictive biomarkers of EGFR TKI efficacy, accurately classifying patients with EGFR-mutant LUAD. In this review, we present the identified metabolic rewiring mechanisms and how these act either independently or in concert with epigenetic or TME elements to orchestrate EGFR TKI resistance. Moreover, we discuss potential nutrient dependencies that emerge, highlighting them as candidate druggable metabolic vulnerabilities with already approved drugs which, in combination with EGFR TKIs, might counteract the solid challenge of resistance, hopefully prolonging the clinical benefit.

Molecular characterization of extrahepatic cholangiocarcinoma: perihilar and distal tumors display divergent genomic and transcriptomic profiles

BACKGROUND

Extrahepatic cholangiocarcinoma (ECC) is classified into two subtypes based on anatomic origin: distal extrahepatic (DECC) and perihilar (PHCC) cholangiocarcinoma. This study aimed to shed light on its genomic and transcriptomic profiles.

RESEARCH DESIGN AND METHODS

The genomic alterations of 99 ECC (47 PHCC and 52 DECC) were investigated by next-generation sequencing of 96 genes. A subgroup of cases, representative of each subtype, was further investigated using transcriptomic analysis. Bioinformatics tools were applied for clustering and pathway analysis and defining the immune composition of the tumor microenvironment.

RESULTS

PHCC had more frequent KRAS mutations (p = 0.0047), whereas TP53 mutations were more common in DECC (p = 0.006). Potentially actionable alterations included high-tumor mutational burden and/or microsatellite instability (7.1%), PI3KCA mutations (8.1%), and MYC (10.1%) and ERBB2 amplification (5.1%). The transcriptomic profiles showed the presence of three distinct clusters, which followed the anatomic origin and differed in immune microenvironment. DECC appeared to contain two distinct tumor subgroups, one enriched for druggable alterations and one lacking actionable opportunities.

CONCLUSIONS

This study provides new insights into the molecular landscape and the actionable alterations of ECC. Our findings represent a step toward improved ECC molecular taxonomy and therapeutic strategies for precision oncology.

Prognostic features of gastro-entero-pancreatic neuroendocrine neoplasms in primary and metastatic sites: Grade, mesenteric tumour deposits and emerging novelties

Updates in classification of gastro-entero-pancreatic neuroendocrine neoplasms better reflect the biological characteristics of these tumours. In the present study, we analysed the characteristics of neuroendocrine tumours that could aid in a more precise stratification of risk groups. In addition, we have highlighted the importance of grade (re)assessment based on investigation of secondary tumour lesions. Two hundred and sixty-four cases of neuroendocrine tumours of gastro-entero-pancreatic origin from three centres were included in the study. Tumour morphology, mitotic count and Ki67 labelling index were evaluated in specimens of primary tumours, lymph node metastases and distant metastases. These variables were correlated with overall survival (OS) and relapse-free survival (RFS). Tumour stage, number of affected lymph nodes, presence of tumour deposits and synchronous/metachronous metastases were tested as possible prognostic features. Mitotic count, Ki-67 labelling index, primary tumour site, tumour stage, presence of tumour deposits and two or more affected lymph nodes were significant predictors of OS and RFS. At the same time, mitotic count and Ki-67 labelling index can be addressed as continuous variables determining prognosis. We observed a very high correlation between the measures of proliferative activity in primary and secondary tumour foci. The presence of isolated tumour deposits was identified as an important determinant of both RFS and OS for pancreatic (hazard ratio [HR] = 7.61, 95% confidence interval [CI] = 3.96-14.6, P < 0.0001 for RFS; HR = 3.28, 95% CI = 1.56-6.87, P = 0.0017 for OS) and ileal/jejunal neuroendocrine tumours (HR = 1.98, 95% CI = 1.25-3.13, P = 0.0036 for RFS and HR 2.59, 95% CI = 1.27-5.26, P = 0.009 for OS). The present study identifies the presence of mesenterial tumour deposits as an important prognostic factor for gastro-entero-pancreatic neuroendocrine tumours, provides evidence that proliferative parameters need to be treated as continuous variables and further supports the importance of grade determination in all available tumour foci.

Cotargeting of miR-126-3p and miR-221-3p inhibits PIK3R2 and PTEN, reducing lung cancer growth and metastasis by blocking AKT and CXCR4 signalling

Lung cancer is the leading cause of cancer‐related death worldwide. Late diagnosis and metastatic dissemination contribute to its low survival rate. Since microRNA (miRNA) deregulation triggers lung carcinogenesis, miRNAs might represent an interesting therapeutic tool for lung cancer management. We identified seven miRNAs, including miR‐126‐3p and miR‐221‐3p, that are deregulated in tumours compared with normal tissues in a series of 38 non‐small‐cell lung cancer patients. A negative correlation between these two miRNAs was associated with poor patient survival. Concomitant miR‐126‐3p replacement and miR‐221‐3p inhibition, but not modulation of either miRNA alone, reduced lung cancer cell viability by inhibiting AKT signalling. PIK3R2 and PTEN were validated as direct targets of miR‐126‐3p and miR‐221‐3p, respectively. Simultaneous miRNA modulation reduced metastatic dissemination of lung cancer cells both in vitro and in vivo through CXCR4 inhibition. Systemic delivery of a combination of miR‐126‐3p mimic and miR‐221‐3p inhibitor encapsulated in lipid nanoparticles reduced lung cancer patient‐derived xenograft growth through blockade of the PIK3R2–AKT pathway. Our findings reveal that cotargeting miR‐126‐3p and miR‐221‐3p to hamper both tumour growth and metastasis could be a new therapeutic approach for lung cancer.

A novel CXCR4 antagonist counteracts paradoxical generation of cisplatin-induced pro-metastatic niches in lung cancer

Platinum-based chemotherapy remains widely used in advanced non-small cell lung cancer (NSCLC) despite experimental evidence of its potential to induce long-term detrimental effects, including the promotion of pro-metastatic microenvironments. In this study, we investigated the interconnected pathways underlying the promotion of cisplatin-induced metastases.

In tumor-free mice, cisplatin treatment resulted in an expansion in the bone marrow of CCR2⁺CXCR4⁺Ly6C^high inflammatory monocytes (IMs) and an increase in lung levels of stromal SDF-1, the CXCR4 ligand. In experimental lung metastasis assays, cisplatin-induced IMs promoted the extravasation of tumor cells and the expansion of CD133⁺CXCR4⁺ metastasis-initiating cells (MICs). Peptide R, a novel CXCR4 inhibitor designed as an SDF-1 mimetic peptide, prevented cisplatin-induced IM expansion, the recruitment of IMs into the lungs, and the promotion of metastasis. At the primary tumor site, cisplatin treatment reduced tumor size while simultaneously inducing tumor release of SDF-1, MIC expansion, and recruitment of pro-invasive CXCR4⁺ macrophages. Co-recruitment of MICs and CCR2⁺CXCR4⁺ IMs to distant SDF-1-enriched sites also promoted spontaneous metastases that were prevented by CXCR4 blockade. In clinical specimens from NSCLC patients SDF-1 levels were found to be higher in platinum-treated samples and related to a worse clinical outcome. Our findings reveal that activation of the CXCR4/SDF-1 axis specifically mediates the pro-metastatic effects of cisplatin and suggest CXCR4 blockade as a possible novel combination strategy to control metastatic disease.

Mixed adenoneuroendocrine carcinoma (MANEC) of the lower gastrointestinal tract: A systematic review with Bayesian hierarchical survival analysis

BACKGROUND

Mixed adeno-neuroendocrine carcinomas (MANEC) are a subgroup of mixed neuroendocrine non-neuroendocrine neoplasms (MiNEN) described as mixed neoplasms containing dual neuroendocrine and non-neuroendocrine components. The aim of this study was to appraise the prevalence of MANEC in the lower gastrointestinal (GI) tract and provide reliable estimates of survival.

METHOD

A systematic review was undertaken in accordance with PRISMA guidelines using PubMed, Embase, Cochrane Library of Systematic Review, Web of Science, and Scopus databases, and a Bayesian hierarchical survival pooled analysis was performed.

RESULTS

Of 182 unique records identified, 71 studies reporting on 752 patients met the inclusion criteria. Mean age was 64.2 ± 13.6, with a male-to-female ratio of 1.25. Overall, 60.3% of MANEC were located in the appendix, 29.3% in the colon, and 10.4% in the anorectum. More than a quarter (29%) of patients had stage IV disease at diagnosis, with higher prevalence in appendiceal than colonic and anorectal primaries. More than 80% had a high-grade (G3) endocrine component. Of the 152 patients followed up for a median of 20 months (interquartile range limits, 16.5-32), median overall survival was 12.3 months (95% credible interval [95%CrI], 11.3-13.7), with a 1.12 [95%CrI, 0.67-1.83] age-adjusted hazard ratio between metastatic and non-metastatic MANEC. Stage IV disease at diagnosis was more prognostically unfavorable in cases of colonic compared to anorectal origin.

CONCLUSION

MANEC is a clinically aggressive pathological entity. The results of this study provide new insights for the understanding of tumor location within the lower GI tract and its prognosis in terms of overall survival.

Does ProCore Fine-Needle Biopsy Really Improve the Clinical Outcome of Endoscopic Ultrasound-Guided Sampling of Pancreatic Masses?

INTRODUCTION

Fine-needle biopsy (FNB) has been suggested to provide better histological samples as compared to endoscopic ultrasound fine-needle aspiration (EUS-FNA). However, studies comparing EUS-FNA and EUS-FNB for pancreatic lesions reported contrasting results. The aim of this study was to compare the clinical performance of EUS-FNA versus EUS-FNB with the ProCore needle for the investigation of pancreatic lesions.

METHODS

We reviewed all patients undergoing EUS for the investigation of pancreatic lesions from August 2012 to September 2018. From August 2012 to January 2015, all procedures were performed with standard needles, whereas from February 2015 to September 2018, the use of ProCore needles had been introduced. Data on diagnostic accuracy, number of needle passes, and/or adverse events were collected.

RESULTS

Three hundred twenty-four patients were retrospectively evaluated: 190 (58.6%) underwent EUS-FNA and 134 (41.4%) EUS-FNB. Both EUS-FNA and EUS-FNB showed high diagnostic accuracy for malignancy (94% [95% CI: 89-97%] vs. 94% [95% CI: 89-98%]). Notably, there were no differences between EUS-FNA and EUS-FNB in terms of sensitivity, specificity, positive and negative likelihood ratio, histological core tissue retrieval, adverse events, or number of needle passes. However, subgroup analysis noted a higher diagnostic accuracy for 25G EUS-FNB as compared to 25G EUS-FNA (85.7 vs. 55.5%; *p = 0.023).

CONCLUSION

EUS-FNB with the ProCore needle is safe and feasible in pancreatic lesions. The ProCore needle did not provide any advantage in terms of diagnostic accuracy, sensitivity, specificity, positive and/or negative likelihood ratio, or acquisition of the core specimen; therefore, its routine application is not supported.

Synaptophysin expression in V600EBRAF-mutated advanced colorectal cancers identifies a new subgroup of tumours with worse prognosis

BACKGROUND

Neuroendocrine differentiation has been extensively associated with worse prognosis and to mechanisms of therapy resistance in several epithelial cancers. A high prevalence of neuroendocrine differentiation was recently described in ^V600EBRAF-mutated (BRAFmt) metastatic colorectal cancers (mCRCs) but no data are available about its prognostic impact in this setting.

METHODS

We assessed synaptophysin immunohistochemical expression in a multi-institutional series of 159 BRAFmt mCRCs with matched clinical and pathological information. Tumours were dichotomized as synaptophysin high and low. Overall survival (OS) and progression-free survival (PFS) were evaluated by Kaplan-Meier and log-rank tests.

RESULTS

Thirty-five tumours (22.0%) showed any level of positivity for synaptophysin, and 18 (11.3%) were characterized by positivity in at least 20% of tumour cells. Four cases resulted 100% synaptophysin positive. The histotype of synaptophysin-positive tumours (i.e. ≥20%) was not otherwise specified in 11 cases (61.1%) and mucinous adenocarcinoma in 4 cases (22.2%). Four cases were DNA mismatch repair deficient (22.2%) and 7 (38.9%) were characterized by a high number of tumour-infiltrating lymphocytes. At multivariate analysis, high synaptophysin expression was a negative independent prognostic factor for both PFS (HR = 2.00, 95% confidence interval [CI] 1.21-3.33, p = 0.006) and OS (HR = 2.27, 95% CI 1.35-3.85, p = 0.001).

CONCLUSIONS

Among BRAFmt mCRCs, synaptophysin-positive tumours are characterized by worse PFS and OS. Further studies should investigate the molecular mechanisms involved in the acquisition of the neuroendocrine phenotype to identify novel-targeted treatment strategies.

Ki-67 Index of 55% Distinguishes Two Groups of Bronchopulmonary Pure and Composite Large Cell Neuroendocrine Carcinomas with Distinct Prognosis

BACKGROUND

Little information is available concerning prognostic factors for bronchopulmonary large cell neuroendocrine carcinomas (BP-LCNECs) and even less is known about combined LCNECs (Co-LCNECs). We investigated whether an integrated morphological, immunohistochemical, and molecular approach could be used for their prognostic evaluation.

METHODS

Morphological (including combined features), proliferative (mitotic count/Ki-67 index), immunohistochemical (napsin A, p40, TTF-1, CD44, OTP, SSTR2A, SSTR5, mASH1, p53, RB1, and MDM2), and genomic (TP53, RB1, ATM, JAK2, KRAS, and STK11) findings were analyzed in BP-LCNECs from 5 Italian centers, and correlated with overall survival (OS). The Ki-67 index was expressed as the percentage of positive cells in hot spots as indicated in the WHO 2019 Digestive System Tumors and, for Co-LCNECs, the Ki-67 index was evaluated only in the LCNEC component.

RESULTS

A total of 111 LCNECs were distinguished into 70 pure LCNECs, 35 Co-LCNECs (27 with adenocarcinoma [ADC] and 8 with squamous cell carcinoma [SqCC]), and 6 LCNECs with only napsin A immunoreactivity. The Ki-67 index cutoff at 55% evaluated in the neuroendocrine component was the most powerful predictor of OS (log-rank p = 0.0001) in all LCNECs; 34 cases had a Ki-67 index <55% (LCNEC-A) and 77 had a Ki-67 index ≥55% (LCNEC-B). Statistically significant differences in OS (log-rank p = 0.0001) were also observed between pure and Co-LCNECs. A significant difference in OS was found between pure LCNECs-A and Co-LCNECs-A (p < 0.05) but not between pure LCNECs-B and Co-LCNECs-B. Co-LCNEC-ADC and LCNEC napsin A+ cases had longer OS than pure LCNEC and Co-LCNEC-SqCC cases (log-rank p = 0.0001). On multivariable analysis, tumor location, pure versus combined features, and napsin A, but no single gene mutation, were significantly associated with OS after adjustment for Ki-67 index and study center (p < 0.05).

CONCLUSIONS

The Ki-67 proliferation index and the morphological characterization of combined features in LCNECs seem to be important tools for predicting clinical outcome in BP-LCNECs.

Molecular epidemiology of fowl adenoviruses in Greece

Outbreaks of inclusion body hepatitis (IBH) and adenoviral gizzard erosion have been anecdotally reported in Greece since approximately 2011. However, a relevant increase in clinical outbreaks compatible with IBH has been described since 2014. Unfortunately, with limited exceptions, only serological assays were performed, and involved strains were not properly characterized. In the present study, 35 outbreaks were investigated in the period between July 2017 and February 2018 in Greece. In addition to clinical and histopathological diagnosis, fowl adenovirus (FAdV) presence was investigated by PCR and sequencing. Thirty-four out of 35 samples tested FAdV positive. Twenty-nine (85.29%) and 5 (14.71%) strains were classified as FAdV-E and FAdV-D, respectively. Fowl adenovirus-E strains were genetically homogeneous and formed an independent cluster of Greek-only sequences, including the sole previously available sequence, suggesting the prolonged circulation of this species in Greece. On the contrary, FAdV-D strains were more heterogeneous and closely related to strains sampled in other European countries, testifying the occurrence of multiple introduction events. The evaluation of phylogenetic relationships, geographic clustering, age of infection, and origin of the broiler breeder flocks suggests that both vertical and horizontal transmission are important in FAdV epidemiology in Greece and highlights the limited efficacy of currently implemented control measures. Of note, a significantly higher mortality was observed in precociously infected flocks, likely because of the higher susceptibility of younger animals. This evidence stresses the need of preventing vertical and/or early infection to limit the economic impact of adenovirus-induced diseases.

Abstract 1106: Cisplatin-induced activation of SDF-1/CXCR4 axis sustains lung cancer metastasis by promoting co-recruitment of metastasis initiating cells and inflammatory monocytes

Background: Platinum-based treatment of locally advanced non-small cell lung cancer (NSCLC) provides some clinical benefit in controlling local disease but is ineffective on metastatic dissemination. Rising evidence suggests that chemotherapy can promote an inflammatory reaction supportive of metastasis growth.We previously demonstrated that cisplatin treatment of mouse xenografts enriches for the chemoresistant fraction of CD133+CXCR4+ lung cancer metastasis initiating cells (MICs), increasing distant metastasis development. We hypothesize here that the SDF-1/CXCR4 axis, implied in MICs migration and in stromal cells trafficking, could play a critical role in cisplatin-induced pro-metastatic effects.

Results: To study the effects of cisplatin in promoting a pre-metastatic niche, tumor-free naïve SCID mice were treated with cisplatin plus/minus peptide R, a novel inhibitor of CXCR4. Cisplatin resulted in a rapid expansion of CCR2+CXCR4+Ly6Chigh inflammatory monocytes (IM) in the bone marrow, concomitantly with their recruitment to murine lungs guided by enhanced endothelial release of SFD-1. Tail-vein injection of H460 human lung cancer cells 72h after cisplatin administration resulted in augmented number of lung metastases enriched in CD133+CXCR4+ MICs. We proposed that the abundance of CXCR4+IM together with increased endothelial permeability caused by cisplatin favors tumor cells extravasations and the expansion of MICs through SDF-1/CXCR4 axis activation. Combination treatment with a CXCR4 inhibitor prevented IM recruitment, MICs expansion and consequently abolished metastasis overgrowth induced by cisplatin. Combination treatment of H460 subcutaneous xenografts in a regimen mimicking clinical setting revealed that cisplatin also caused tumor release of SDF-1 able to trigger local expansion of MICs subset and to recruit CXCR4+tumor associated macrophages involved in tumor cells intravasation. Stromal SDF-1 induced by cisplatin at distant site also co-recruited MICs and CCR2+CXCR4+IM, promoting spontaneous metastasis formation that can be counteracted by CXCR4 blockade. We confirmed in clinical setting that platinum-based neoadjuvant treatment of NSCLC patients significantly increases tumor SDF-1 expression. Moreover, an higher expression of tumor SDF-1 after cisplatin neo-adjuvant treatment was associated with patients' shorter DFS (p=0,0056; Hazards Ratio= 3,1) and poor OS (p=0,029; Hazards Ratio= 3,46).

Conclusions: Our data reveal a paradoxical pro-metastatic effect of cisplatin that fosters MIC-IM recruitment and cross-talk via SDF-1/CXCR4 axis activation. A new combination strategy based on CXCR4 inhibition may disrupt these interactions, providing more effective results for lung cancer treatment

Citation Format: Giulia Bertolini, Valeria Cancila, Orazio Fortunato, Giuseppe Lo Russo, Monica Tortoreto, Giovanni Centonze, Massimo Milione, Claudio Tripodo, Stefania Scala, Gabriella Sozzi, Luca Roz. Cisplatin-induced activation of SDF-1/CXCR4 axis sustains lung cancer metastasis by promoting co-recruitment of metastasis initiating cells and inflammatory monocytes [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 1106.

Prognostic impact of immune-microenvironment in colorectal liver metastases resected after triplets plus a biologic agent: A pooled analysis of five prospective trials

BACKGROUND

Immune-contexture of tumour microenvironment (TME) influences prognosis of colorectal cancer (CRC) patients and can be altered by cytotoxic and targeted agents. Limited data are available regarding the immune-TME of CRC after treatment.

METHODS

An extensive immunohistochemistry evaluation of immunological parameters on tumour cells and TME of colorectal liver metastases from 106 patients who underwent secondary resection, after receiving triplets FOLFOXIRI (5-fluorouracil, oxaliplatin and irinotecan) or COI (capecitabine, oxaliplatin and irinotecan) plus bevacizumab (N = 59) or cetuximab (N = 47) in five first-line no-profit clinical trials was performed.

RESULTS

No substantial differences were reported in immunological parameters according to administered targeted agent, RAS/BRAF mutational status and histopathological or Response Evaluation Criteria in Solid Tumours response. Stromal expression of Cyclooxygenase-2 (COX-2) (p = 0.002), Human leukocyte antigen (HLA) (p = 0.003) and Programmed cell death protein 1 (PD1) (p = 0.002) were independent prognostic factors for longer relapse-free survival (RFS) at multivariate analysis with a positive trend for post-resection overall survival (OS). Patients whose metastases expressed stromal COX-2, HLA and PD1 (inflamed-score positive) reported longer RFS (25.5 versus 9.8 months; p < 0.001) and post-resection OS (64.3 versus 37.7 months; p = 0.003) as compared with others. In addition, patients with higher expression of CD4 and CD8 T-cells in tumour core and invasive margin (CD4/CD8-score) showed a better post-resection OS (not-reached versus 41.6 months; p = 0.032). A combined score of inflamed-score and CD4/CD8-score (combo-score) showed a clear prognostic role.

CONCLUSIONS

The present study emphasises the role of immune-TME as independent predictor of survival in patients resected after triplets plus biologic. Inflamed-, CD4/C8- and combo-scores should be confirmed as prognostic factors in further studies.

TLR3 Expression Induces Apoptosis in Human Non-Small-Cell Lung Cancer

The prognostic value of Toll-like receptor 3 (TLR3) is debated in cancer, differing between tumor types, methods, and cell types. We recently showed for the first time that TLR3 expression on early stage non-small-cell lung cancer (NSCLC) results associated with a good prognosis. Here, we provide experimental evidences explaining the molecular reason behind TLR3’s favorable prognostic role. We demonstrated that TLR3 activation in vitro induces apoptosis in lung cancer cell lines and, accordingly, that TLR3 expression is associated with caspase-3 activation in adenocarcinoma NSCLC specimens, both evaluated by immunohistochemistry. Moreover, we showed that TLR3 expression on cancer cells contributes to activate the CD103+ lung dendritic cell subset, that is specifically associated with processing of antigens derived from apoptotic cells and their presentation to CD8+ T lymphocytes. These findings point to the relevant role of TLR3 expression on lung cancer cells and support the use of TLR3 agonists in NSCLC patients to re-activate local innate immune response.

Gastroenteropancreatic High-Grade Neuroendocrine Neoplasms: Histology and Molecular Analysis, Two Sides of the Same Coin

BACKGROUND

In gastroenteropancreatic (GEP) high-grade neuroendocrine neoplasms (H-NENs), Ki-67 threshold of 55% defines three prognosis subclasses: neuroendocrine tumor (NET) G3, neuroendocrine carcinoma (NEC) <55%, and NEC ≥55%. We investigated whether the molecular profiling of H-NENs differs among these subcategories and evaluated potential therapeutic targets, including PD-L1.

METHODS

In GEP-NEN patients, we evaluated: (i) 55% threshold for Ki-67 labeling index for further stratifying NEC and (ii) immunoreactivity and gene mutations by immunohistochemistry and targeted next-generation sequencing (T-NGS).

RESULTS

Fifteen NETs G3 and 39 NECs were identified. Ki-67 labeling index was <55% in 9 NECs and ≥55% in 30 NECs. Gene mutations by NGS (TP53, 32.9%; KRAS, 5.5%; BRAF, 4.1%) were detected in 46.6% NENs, significantly enriched in NEC ≥55% (76.7%) compared to NEC <55% (55.6%) or NET (20.0%). PD-L1 staining in tumor-infiltrating lymphocytes was observed in NEC ≥55% (36.7%; p = 0.03). Median OS was 4.3 years in NET G3, 1.8 years in NEC <55%, and 0.7 years in NEC ≥55% (p <0.0001); it was 2.3 years with NGS wild-type, 0.7 years with ≥1 mutation (p <0.0001), 0.8 years in PD-L1-positive patients, and 1.7 years in PD-L1-negative subjects (p = 0.0004). In multivariate analysis, only the proposed subclassification approach yielded statistically significant differences between groups (NEC <55% vs. NET G3, HR 14.1, 95% CI 2.2-89.8, p = 0.005; NEC ≥55% vs. NET G3, HR 25.8, 95% CI 3.9-169, p = 0.0007).

CONCLUSIONS

These findings identify NEC ≥55% as a biologically and prognostically distinct subtype and pave the way for more personalized treatment.

Toll-like receptor 3 as a new marker to detect high risk early stage Non-Small-Cell Lung Cancer patients

Immune and epithelial cells express TLR3, a receptor deputed to respond to microbial signals activating the immune response. The prognostic value of TLR3 in cancer is debated and no data are currently available in NSCLC, for which therapeutic approaches that target the immune system are providing encouraging results. Dissecting the lung immune microenvironment could provide new prognostic markers, especially for early stage NSCLC for which surgery is the only treatment option. In this study we investigated the expression and the prognostic value of TLR3 on both tumor and immune compartments of stage I NSCLCs. In a cohort of 194 NSCLC stage I, TLR3 immunohistochemistry expression on tumor cells predicted a favorable outcome of early stage NSCLC, whereas on the immune cells infiltrating the tumor stroma, TLR3 expression associated with a poor overall survival. Patients with TLR3-positive immune infiltrating cells, but not tumor cells showed a worse prognosis compared with all other patients. The majority of TLR3-expressing immune cells resulted to be macrophages and TLR3 expression associates with PD-1 expression. TLR3 has an opposite prognostic significance when expressed on tumor or immune cells in early stage NCSCL. Analysis of TLR3 in tumor and immune cells can help in identifying high risk stage I patients for which adjuvant treatment would be beneficial.

Age-Related Alterations in Immune Contexture Are Associated with Aggressiveness in Rhabdomyosarcoma

Adolescents and young adults (AYA) with rhabdomyosarcoma (RMS) form a subgroup of patients whose optimal clinical management and access to care remain a challenge and whose survival lacks behind that of children diagnosed with histologically similar tumors. Understanding the tumor biology that differentiates children from AYA-RMS could provide critical information and drive new initiatives to improve the final outcome. MicroRNA (miRNA) and gene expression profiling (GEP) was evaluated in a RMS cohort of 49 tumor and 15 non-neoplastic tissues. miRNAs analysis identified miR-223 over-expression and miR-431 down-regulation in AYA, validated by Real-Time PCR and miRNA in situ hybridization (ISH). GEP analysis detected 793 age-correlated genes in tumors, of which 194 were anti-correlated. NOTCH2, FGFR1/2 were significantly down-modulated in AYA-RMS. miR-223 was associated with up-regulation of epithelial mesenchymal translation (EMT) and inflammatory pathways, whereas miR-431 was correlated to myogenic differentiation and muscle metabolism. GEP showed an increase in genes associated with CD4 memory resting cells and a decrease in genes associated with γδ T-cells in AYA-RMS. Immunohistochemistry (IHC) analysis demonstrated an increase of infiltrated CD4, CD8, and neutrophils in AYA-RMS tumors. Our results show that aggressiveness of AYA-RMS could be explained by differences in microenvironmental signal modulation mediated by tumor cells, suggesting a fundamental role of immune contexture in AYA-RMS development.

Coated cationic lipid-nanoparticles entrapping miR-660 inhibit tumor growth in patient-derived xenografts lung cancer models

Lung cancer is the leading cause of cancer-related deaths. Late diagnosis and inadequate therapies contribute to poor outcomes. MicroRNAs (miRNAs) are small non-coding RNAs and are involved in lung cancer development. Because miRNAs simultaneously regulate several cancer-related genes, they represent an interesting therapeutic approach for cancer treatment. We have developed Coated Cationic Lipid-nanoparticles entrapping miR-660 (CCL660) and intraperitoneally administered (1.5 mg/Kg) twice a week for four weeks into SCID mice carrying subcutaneously lung cancer Patients Derived Xenografts (PDXs). Obtained data demonstrated that miR-660 is down-regulated in lung cancer patients and that its replacement inhibited lung cancer growth by inhibiting the MDM2-P53 axis. Furthermore, systemic delivery of CCL660 increased miRNA levels in tumors and significantly reduced tumor growth in two different P53 wild-type PDXs without off-target effects. MiR-660 administration reduced cancer cells proliferation by inhibiting MDM2 and restoring P53 function and its downstream effectors such as p21. Interestingly, anti-tumoral effects of CCL660 also in P53 mutant PDXs but with a functional p21 pathway were observed. Stable miR-660 expression inhibited the capacity of H460 metastatic lung cancer cells to form lung nodules when injected intravenously into SCID mice suggesting a potential role of miR-660 in metastatic dissemination. To investigate the potential toxic effects of both miRNAs and delivery agents, an in vitro approach revealed that miR-660 replacement did not induce any changes in both mouse and human normal cells. Interestingly, lipid-nanoparticle delivery of synthetic miR-660 had no immunological off-target or acute/chronic toxic effects on immunocompetent mice. Altogether, our results highlight the potential role of coated cationic lipid-nanoparticles entrapping miR-660 in lung cancer treatment without inducing immune-related toxic effects.

Microenvironment and tumor inflammatory features improve prognostic prediction in gastro-entero-pancreatic neuroendocrine neoplasms

Microenvironment‐related immune and inflammatory markers, when combined with established Ki‐67 and morphology parameters, can improve prognostic prediction in gastro‐entero‐pancreatic neuroendocrine neoplasms (GEP‐NENs). Therefore, we evaluated the prognostic value of microenvironment and tumor inflammatory features (MoTIFs) in GEP‐NENs. For this purpose, formalin‐fixed paraffin‐embedded tissue sections from 350 patients were profiled by immunohistochemistry for immune, inflammatory, angiogenesis, proliferation, NEN‐, and fibroblast‐related markers. A total of 314 patients were used to generate overall survival (OS) and disease‐free survival (DFS) MoTIFs prognostic indices (PIs). PIs and additional variables were assessed using Cox models to generate nomograms for predicting 5‐year OS and DFS. A total of 36 patients were used for external validation of PIs and nomograms' prognostic segregations. From our analysis, G1/G2 versus G3 GEP‐NENs showed phenotypic divergence with immune‐inflammatory markers. HLA, CD3, CD8, and PD‐1/PD‐L1 IHC expression separated G3 into two sub‐categories with high versus low adaptive immunity‐related features. MoTIFs PI for OS based on COX‐2^Tumor(T) > 4, PD‐1^Stromal(S) > 0, CD8^S < 1, and HLA‐I^S < 1 was associated with worst survival (hazard ratio [HR] 2.50; 95% confidence interval [CI], 2.12–2.96; p < 0.0001). MoTIFs PI for DFS was based on COX‐2^T > 4, PD‐1^S > 4, HLA‐I^S < 1, HLA‐I^T < 2, HLA‐DR^S < 6 (HR 1.77; 95% CI, 1.58–1.99; p < 0.0001). Two nomograms were developed including morphology (HR 4.83; 95% CI, 2.30–10.15; p < 0.001) and Ki‐67 (HR 11.32; 95% CI, 5.28–24.24; p < 0.001) for OS, and morphology (PI = 0: HR 10.23; 95% CI, 5.67–18.47; PI = 5: HR 2.87; 95% CI, 1.21–6.81; p < 0.001) and MoTIFs PI for DFS in well‐differentiated GEP‐NENs (HR 6.21; 95% CI, 2.52–13.31; p < 0.001). We conclude that G1/G2 to G3 transition is associated with immune‐inflammatory profile changes; in fact, MoTIFs combined with morphology and Ki‐67 improve 5‐year DFS prediction in GEP‐NENs. The immune context of a subset of G3 poorly differentiated tumors is consistent with activation of adaptive immunity, suggesting a potential for responsiveness to immunotherapy targeting immune checkpoints.

Antibody-Fc/FcR Interaction on Macrophages as a Mechanism for Hyperprogressive Disease in Non-small Cell Lung Cancer Subsequent to PD-1/PD-L1 Blockade

PURPOSE

Hyperprogression (HP), a paradoxical boost in tumor growth, was described in a subset of patients treated with immune checkpoint inhibitors (ICI). Neither clinicopathologic features nor biological mechanisms associated with HP have been identified.

EXPERIMENTAL DESIGN

Among 187 patients with non-small cell lung cancer (NSCLC) treated with ICI at our institute, cases with HP were identified according to clinical and radiologic criteria. Baseline histologic samples from patients treated with ICI were evaluated by IHC for myeloid and lymphoid markers. T-cell-deficient mice, injected with human lung cancer cells and patient-derived xenografts (PDX) belonging to specific mutational subsets, were assessed for tumor growth after treatment with antibodies against mouse and human programmed death receptor-1 (PD-1). The immune microenvironment was evaluated by flow cytometry and IHC.

RESULTS

Among 187 patients, 152 were evaluable for clinical response. We identified four categories: 32 cases were defined as responders (21%), 42 patients with stable disease (27.7%), 39 cases were defined as progressors (25.7%), and 39 patients with HP (25.7%). Pretreatment tissue samples from all patients with HP showed tumor infiltration by M2-like CD163⁺CD33⁺PD-L1⁺ clustered epithelioid macrophages. Enrichment by tumor-associated macrophages (TAM) was observed, even in tumor nodules from immunodeficient mice injected with human lung cancer cells and with PDXs. In these models, tumor growth was enhanced by treatment with anti-PD-1 but not anti-PD-1 F(ab)₂ fragments.

CONCLUSIONS

These results suggest a crucial role of TAM reprogramming, upon Fc receptor engagement by ICI, eventually inducing HP and provide clues on a distinctive immunophenotype potentially able to predict HP.See related commentary by Knorr and Ravetch, p. 904.

Impact of systemic and tumor lipid metabolism on everolimus efficacy in advanced pancreatic neuroendocrine tumors (pNETs)

The mTOR inhibitor everolimus is effective against advanced pancreatic neuroendocrine tumors (pNETs). However, it can cause metabolic adverse events, such as hyperglycemia, hypertriglyceridemia and hypercholesterolemia. In this work we aimed at evaluating the impact of systemic and tumor lipid metabolism on everolimus efficacy. We carried out a monocentric, retrospective study to correlate plasma triglyceride and cholesterol levels with the progression free survival (PFS) of advanced pNET patients treated with everolimus. In formalin fixed, paraffin embedded (FFPE) tumor specimens, we also assessed by mRNA quantification and immunohistochemistry the expression of acetyl-CoA carboxylase 1 (ACC1) and fatty acid synthase (FASN), two enzymes crucially involved in fatty acid biosynthesis, and we analyzed their impact on PFS. We evaluated 58 consecutive pNET patients who started everolimus between December 2006 and January 2015. Patients with higher plasma triglycerides during the first 3 months of treatment had an increased risk of disease progression (aHR 3.08, 95% CIs 1.15-8.21; p = 0.025). In 23 FFPE tumor specimens amenable for IHC evaluations, we found a positive correlation between ACC1 and FASN at both mRNA (r = 0.87, p = 0.00045) and protein (r = 0.68, p = 0.0004) level. Patients with higher ACC1 protein expression in metastatic lesions had significantly lower PFS when compared to patients with lower ACC1 levels (5.5 vs. 36 months; aHR 4.49, 95% CIs 1.08-18.72; p = 0.039). In conclusion, systemic and tumor lipid metabolism are associated with the PFS of everolimus-treated patients with advanced pNETs; based on these findings, dietary and pharmacological interventions targeting lipid metabolism could improve everolimus efficacy in this patient population.