P11.26.A STAT3 expression in brain metastases from breast cancer: correlations with different molecular subtypes and clinical outcome

Background

STAT3 expression in peritumoral reactive astrocytes (RA) of brain metastases (BM) may favor a pro-metastatic environment. The aim of the study was to evaluate in a retrospective cohort of surgically resected BM from breast cancer (BC) the expression of pSTAT3 in RA of peritumoral tissue of BM, identify different patterns of expression according to molecular subtypes, and correlate with intracranial progression-free survival (i-PFS).

Material and Methods

Patients with histologically proven BM diagnosis from BC were identified from the biobank of Pathology Unit of University of Turin and Spanish national BrM network (RENACER). pSTAT3 expression was evaluated and scored in RA of peritumoral tissue using GFAP and STAT3 immunohistochemistry, according to Priego et al. (Nat Med 2018). Data on histological diagnosis, molecular subtypes, and i-PFS were retrieved by chart review. Intracranial progression was defined based on MRI reports.

Results

Eighty-five BM specimens from BC of 85 female patients with a median age of 54 years (range 30-81 years) were available for analysis. Immunohistochemistry for GFAP and pSTAT3 was feasible in 68/85 (80%). Fifteen out of 68 patients (21.1%) had BM from luminal BC, 27/68 (39.7%) from HER2-positive BC, and 26/68 (39.2%) from TNBC. Fifty-six out of 68 (82.4%) showed positive staining of pSTAT3 in peritumoral RA, of which 9/68 (13.3%) scored with 3, 26/68 (38.2%) with 2, and 21/68 (30.9%%) with 1, while pSTAT3 expression was negative (score 0) in 12/68 (17.6%). High pSTAT3 expression (score 2-3) was observed in 17/27 (62.9%) BM from HER2-positive BC and in 15/26 (57.7%) BM from TNBC, while most of BM from luminal BC (12/15 - 80%) had low or absent pSTAT3 (score 0-1) (p=0.021). Overall i-PFS was 16 months (range 7-41): low pSTAT3 BM (score 0-1) had a median i-PFS of 21 months versus 12 months for high pSTAT3 BM (score 2-3). A shorter median i-PFS was observed in high pSTAT3 BM from TNBC (4 months) as compared with low pSTAT3 BM (11 months). Conversely, i-PFS of high pSTAT3 BM (7 months) was similar to low pSTAT3 BM (6 months) in HER2-positive BC.

Conclusion

pSTAT3 expression in RA of peritumoral tissue of BM from TNBC and HER2-positive BC is higher than in BM from luminal BC. Of note, patients with high pSTAT3 BM from TNBC progressed earlier in comparison with those with low pSTAT3, suggesting that pSTAT3 expression has an influence on the outcome.

JS06.4.A Intracranial ependymomas of the adult: outcome and response to treatments across molecular subtypes

Background

The 2021 WHO Classification lists two molecularly defined types of supratentorial ependymomas (STEs), i.e., ZFTA and YAP1 fusions, and posterior fossa ependymomas (PFEs), i.e, PFA and PFB. Based on retrospective data, the presence of the ZFTA fusion (for STEs) and the PFA subtype (for PFEs) seem to correlate with a poorer outcome. However, prospective data on large cohorts of adult patients are lacking, and the role of treatments is uncertain. The aim of our study is to investigate the clinical characteristics, response to treatment, and outcome of a cohort of adult patients with supratentorial and posterior fossa ependymomas across different molecular subtypes.

Patients and Methods

Clinical data of patients ≥18 years with STEs and PFEs were retrospectively collected from 2 Italian Centres (Turin, Treviso). ZFTA and YAP1 fusions were detected by FISH, while PFA and PFB subtypes were defined by anti-H3K27me3 immunohistochemistry.

Results

We collected 42 adult patients with STEs (11, 26.2%) and PFEs (31, 73.8%) diagnosed between 1984 and 2021. Median age was 45 years. ZFTA and YAP1 fusions were found in 5 (45.5%) and 1 (9.1%) case of STEs. PFA and PFB subtypes accounted for 9 (29.0%) and 22 (71.0%) cases of PFEs. Extent of resection (EOR) was gross-total (GTR) in 6/11 (54.8%) STEs and 17/31 PFEs (54.8%). 4/11 (36.4%) STEs and 9/31 (29.0%) PFEs received adjuvant radiotherapy (RT). Median progression-free survival (mPFS) and overall survival (mOS) were 172 and 61.6 months for STEs patients, and not reached (NR) and 332 months for PFEs. For patients with STEs, the presence of ZFTA fusion correlated with a significant shorter PFS (64.0 months vs NR, p = 0.05) and with a trend for shorter mOS (168.0 months vs NR, p = 0.307). The only patient with YAP1 fusion had a very long PFS (33 years). In a multivariable analysis, EOR and adjuvant RT did not significantly affect survival of STEs patients.For patients with PFEs, PFA and PFB subtypes did not differ significantly in terms of mPFS (NR vs 137.0 months, p = 0.513) and mOS (NR vs NR, p = 0.132). Conversely, GTR was associated with a significantly longer mPFS (NR vs 63.0 months, p = 0.007) and with a trend for longer mOS (NR vs 332.0 months, p = 0.146). In a multivariable analysis, GTR was associated with a significantly lower risk of disease progression, both in the entire cohort of PFE patients (p = 0.016), and within the PFA subtype (p = 0.013). Similarly, GTR was associated with a trend for better PFS within the PFB subtype.

Conclusion

Our preliminary data on a real-life cohort of adult patients confirm the worse prognosis of STEs harbouring the ZFTA fusion and suggest an impact of the EOR among PFEs regardless of molecular subtypes. Larger populations of patients are needed to better define the role of treatment modalities within molecular subrogups. The study is still ongoing in a multicentric setting.

OS08.4.A Analysis of melanoma brain metastasis immune microenvironment through multiplex gene expression profiling

Background

Novel immunotherapies based on targeting of specific immune checkpoints enabled a significant improvement of melanoma outcome, but melanoma brain metastases (BM) remain an unmet oncological need with an overall 2-year survival rate lower than 10%. Tumour immune microenvironment has been demonstrated to play a key role in BM establishment and development, but data regarding the specific milieu of melanoma BM is limited.

Material and Methods

Gene expression profiles of 55 samples of primary melanoma and BM were evaluated using the nCounter PanCancer IO 360 Panel (NanoString Technologies) targeting 770 mRNA involved in tumor immune microenvironment modulation. The case series consisted of 10 primary melanomas and their 10 matched BM, 25 unmatched BM, and 10 locally advanced control melanomas without evidence of BM after >5 year follow up.

Results

Among BM samples, most patients (25/45) were males and median age at BM diagnosis was 61,2 years with a median time to BM development of 2,1 years. Median OS from BM diagnosis was 1,3 years. Several genes resulted significantly downregulated in BM compared to primary melanomas, including SERPINB5 (p<0.001), ARG1 (p=0.0067), S100A8 (p<0.001), S100A9 (p<0.001), S100A12 (p=0.0037), IL1RN (p=0.0012), CCL21 (p=0.0012), CCL22 (p=0.0012) and CCL13 (p=0.037) and SELE (p=0.026); conversely, C7 was upregulated (p<0.001). Downregulated signatures in BM involved those associated with multiple immune cell populations, including neutrophils, dendritic cells, mast cells and Treg, as well as inflammatory chemokines, the CTLA4 immune checkpoint and ARG1 enzyme function; conversely, MAGEs-related signature was upregulated. Comparison between primary melanomas which developed BM and those which did not showed a significant overexpression of RRM2 (p=0.0247) and TNFRSF1A (p=0.032) genes in the latter group and an upregulation of the PD-1 pathway. Analysis according to tumour mutational status showed an upregulation of signatures associated with inflammatory chemokines, dendritic and myeloid cells and neutrophils. No differences were observed according to time to BM development and survival from BM diagnosis.

Conclusion

Our findings show that melanoma BM harbor distinct immunosuppressive mechanisms compared to primary tumors: this data elicits the importance of investigating the heterogeneity of BM microenvironment. Genes and pathways selectively overexpressed or downregulated in melanoma BM should be validated to be possibly considered as novel therapeutic targets.

OS06.7A METPlatform identifies brain metastasis vulnerabilities and predicts patient response to therapy

BACKGROUND

The diagnosis of brain metastasis involves high morbidity and mortality and remains an unmet clinical need in spite of being the most common tumor in the brain. Exclusion of these cancer patients from clinical trials is a major cause of their limited therapeutic options.

MATERIAL AND METHODS

We report a novel drug-screening platform (METPlatform) based on organotypic cultures which allows identifying effective anti-metastasis agents in the presence of the organ microenvironment. We have applied this approach to clinically relevant stages of brain metastasis using both experimental models and human tumor tissue (by performing patient-derived organotypic cultures - PDOCs -). We have also used METPlatform to perform unbiased proteomics of brain metastases in situ to identify potential novel mediators of this disease and explore resistance mechanisms to targeted therapy. Finally, we have exploited METPlatform as “avatars” to predict response to therapy in patients with primary brain tumors.

RESULTS

We identified heat shock protein 90 (HSP90) as a promising therapeutic target for brain metastasis. DEBIO-0932, a blood-brain barrier permeable HSP90 inhibitor, shows high potency against mouse and human brain metastases from different primary origin and oncogenomic profile at clinically relevant stages of the disease, including a novel model of local relapse after neurosurgery. Furthermore, in situ proteomic analysis of brain metastases treated with the chaperone inhibitor revealed non-canonical clients of HSP90 as potential novel mediators of brain metastasis and actionable mechanisms of resistance driven by autophagy. Combined therapy using HSP90 and autophagy inhibitors showed synergistic effects compared to sublethal concentrations of each monotherapy, demonstrating the potential of METPlatform to design and test rationale combination therapies to target metastasis more effectively. Finally, we show that brain tumor PDOCs predict the response of the corresponding patient to standard of care, thus proving the potential of METPlatform for improving personalized care in cancer.

CONCLUSION

Our work validates METPlatform as a potent resource for metastasis research integrating drug-screening and unbiased omic approaches that is fully compatible with human samples and questions the rationale of excluding patients with brain metastasis from clinical trials. We envision that METPlatform will be established as a clinically relevant strategy to personalize the management of metastatic disease in the brain and elsewhere.

The post-surgical era of GBM: How molecular biology has impacted on our clinical management. A review

Glioblastoma (GBM) is the most common glioma in adults, with incidence increasing by 3% per year. According to the World Health Organization Classification of Central Nervous System Tumors, GBM is considered a grade IV tumor due to its malignant behavior. The aim of this review is to summarize the main biological aspects of GBM. In particular, we focused our attention on those alterations which have been proven to have an impact on patients' outcome, mainly in terms of overall survival (OS), or on the tumor response to therapies. We have also analyzed the cellular biology and the interactions between GBM and the surrounding environment.

Review: Peering through a keyhole: liquid biopsy in primary and metastatic central nervous system tumours

Tumour molecular profiling by liquid biopsy is being investigated for a wide range of research and clinical purposes. The possibility of repeatedly interrogating the tumour profile using minimally invasive procedures is helping to understand spatial and temporal tumour heterogeneity, and to shed a light on mechanisms of resistance to targeted therapies. Moreover, this approach has been already implemented in clinical practice to address specific decisions regarding patients’ follow‐up and therapeutic management. For central nervous system (CNS) tumours, molecular profiling is particularly relevant for the proper characterization of primary neoplasms, while CNS metastases can significantly diverge from primary disease or extra‐CNS metastases, thus compelling a dedicated assessment. Based on these considerations, effective liquid biopsy tools for CNS tumours are highly warranted and a significant amount of data have been accrued over the last few years. These results have shown that liquid biopsy can provide clinically meaningful information about both primary and metastatic CNS tumours, but specific considerations must be taken into account, for example, when choosing the source of liquid biopsy. Nevertheless, this approach is especially attractive for CNS tumours, as repeated tumour sampling is not feasible. The aim of our review was to thoroughly report the state‐of‐the‐art regarding the opportunities and challenges posed by liquid biopsy in both primary and secondary CNS tumours.

Anti-angiogenic approaches to malignant gliomas

Despite advances in multidisciplinary approaches, the prognosis for most patients with malignant gliomas is poor. Malignant gliomas are highly vascularized tumors with elevated expression of vascular endothelial growth factor (VEGF), an important mediator of angiogenesis. Recent studies of bevacizumab, an anti-VEGF monoclonal antibody, alone or associated with chemotherapy, have demonstrated high response rates and prolongation of median and 6-month progression-free survival. Clinical evaluation of several multitarget small molecule tyrosine kinase inhibitors is ongoing. Other promising antiangiogenic compounds are cilengitide and continuous temozolomide. Toxicity is acceptable. Open issues are represented by patterns of tumor progression, resistance mechanisms and biomarkers.

Asphaltene Adsorption Onto Formation Rock: An Approach to Asphaltene Formation Damage Prevention

Summary

In this paper, through a comparative study on static vs dynamic adsorption of asphaltene onto formation rock, it is reported how, for the particular asphaltene/formation rock system here considered, the Dynamic asphaltene adsorption onto formation rock is a continuous phenomenon by which the quantity of adsorbed asphaltene increases continuously. In our opinion this rather remarkable adsorption behaviour may contribute to asphaltene formation damage. In the hypothesis that "prevention" may represent a more economical approach than "removal", in this work is also reported a possible "prevention approach" based on formation rock treatment by means of specific chemicals more apt than asphaltenes to be adsorbed onto rock. As preliminary demonstration, with the aim at assessing qualitatively the potential of our approach, we have pre-treated the rock by means of commercially available asphaltene dispersant and flocculation inhibitor. Albeit the chosen additives are not commercialised on the base of their specific adsorption feature, a prevention effect has been effectively found. Experimental set ups and procedures used as a base for a test able to rank chemicals with respect to their "asphaltene adsorption" inhibitive effects are also reported.

Introduction

Owing to their polar character, asphaltene do adsorb onto formation rock surface. The extent of adsorption is controlled by a number of factors the most significant of which are: chemical and structural nature of the crude-oil and mineral substrate, "in situ" T, P values and the specific flowing system. As a consequence, the resulting adsorbed asphaltene layers induce wettability alteration of the oil-bearing formation. Beside wettability alteration, the adsorbed asphaltenes may induce a more direct type of formation damage as we found during an experimental study on the behaviour of Static and Dynamic asphaltene adsorption onto formation rock. In such study, through core-flood experiments we found a peculiar and intriguing asphaltene Dynamic adsorption behaviour quite different with respect to the one obtained, for the same asphaltene/formation rock couple, when studying the Adsorption Isotherm. More precisely, while in the Static regime the asphaltenes do saturate the rock (Langmuir Type 1 Isotherm), in the Dynamic regime the saturation condition is not attained. In other words, we have got experimental indications that in Dynamic regime, for that specific asphaltene/formation rock system, the asphaltene adsorption onto formation rock is a continuous phenomenon by which the quantity of adsorbed asphaltene increases as a function of the flowing time. Extrapolating this experimental result to the real field situation, we may observe that this not conventional phenomenon should be able to induce asphaltene formation damage by pore throats blocking.

Chemical Equilibrium Models: Their Use in Simulating the Injection of Incompatible Waters

Summary.

One of the problems encountered in waterflooding projects is scale formation caused by chemical incompatibility between potential injection waters and reservoir brine. Chemical compatibility evaluation through laboratory experiments on cores at reservoir conditions is of limited value because only first-contact phenomena are reproduced. A numerical model is presented that couples a reservoir-fluid-flow/ thermal-equilibrium simulator with a chemical-equilibrium computer code. This model, AGIPS, enables us to calculate the evolution in time of the amount of scale formed at any point in the reservoir and inside the wells when changes occur in the temperature of the injected water and when the injection water mixes with reservoir brine. Moreover, the model calculates temperature and pressure profiles in the reservoir, together with their evolution in time, taking into account the permeability reduction caused by scale formation. Results are presented for the chemical-equilibrium code validation by matching experimental data on scale formation in mixtures of incompatible waters. An example is also given of the use of AGIPS in simulating a five-spot waterflood where incompatible water is injected.

Introduction

Water injection to improve oil recovery is a long-standing practice in the oil industry. Pressure maintenance by water injection in the early stages of field exploitation or secondary recovery by peripheral and pattern waterflooding both call for huge amounts of water to be injected into oil reservoirs. The selection of the injection water is a crucial factor when waterflood operations are planned. In offshore oil fields, the most obvious (and the cheapest) source of water is the sea; in onshore fields, waters from shallow aquifers are normally used for injection. River water is used only when no other source is available because of the high content of suspended matter and micro-organisms usually present. In all cases, the prerequisite for good injection water is present. In all cases, the prerequisite for good injection water is that it must not impair well injectivity and reservoir fluid characteristics. Injection water must be free of suspended particles, organic matter, oxygen, and acid gases (CO2 and H2S) before it is pumped into the injection wells. pumped into the injection wells. Fine inorganic particles in the injected water may form a cake at the well bottom and plug the injection well. Algae and other living organisms may grow at reservoir level, forming a gelatinous body that impairs injectivity. Backwashing and acid washing are the usual well treatments adopted when these troubles occur. Bacteria introduced into the reservoir in the injection water may grow and travel through the formation and may metabolize both formation oil and brine. Although microbial EOR is being considered as a potential process for improving oil recovery, people in the industry still consider the introduction of bacteria into an oil reservoir a source of trouble. This is particularly true when sulfate-reducing bacteria are present in the injection water because they metabolize the reservoir brine, forming H2S. The continuous or batch addition of bacteria-killing chemicals is a must in every injection process. The presence of oxygen and acid gases in the injection water causes corrosion in both surface and well equipment, jeopardizing the safe operation of this equipment. Moreover, corrosion scale transported in the injection water may accumulate at the well bottom and plug it. Degassing the injection water under vacuum or stripping with hydrocarbon gases is common practice in the oil industry. Once the water enters the oil-bearing formation, two more problems arise: compatibility of the injection water with the reservoir rock and with the reservoir brine. Reservoir rocks often contain shales, dispersed in the pores, finely interlaminated, or interbedded in the pay. The shales are in equilibrium with the reservoir brine: any change in the ionic strength (as a first approximation, in the salinity) of the environment induces a rearrangement of the shale particles. If the salinity of the injection water is higher than that of the reservoir brine, the shale structure collapses. Shale lamellae are thus freed, and while they move about in the injection water they may plug parts of the formation, usually the most permeable parts. This plug parts of the formation, usually the most permeable parts. This may result in a reduction of rock heterogeneity and therefore in an improvement in oil displacement. When the salinity of the injection water is lower than that of the reservoir brine, the shale structure swells. This causes a reduction in the permeability of the (less permeable) shaly layers of the reservoir rock and thus an increase in the heterogeneity of rock permeability. As a consequence, oil recovery is impaired. Moreover, the injected water may dissolve minerals present in the reservoir rock. As a consequence, the composition of the injected water is changed, and this may affect its compatibility with the reservoir brine. A more controversial question is whether injection water should be totally compatible with reservoir brine (i.e., the formation of any insoluble matter, or scale, when the injection water mixes with reservoir brine should be considered unacceptable) or whether a certain degree of incompatibility can be tolerated. This point will be discussed in detail later.

Scale Formation Along the Injection-Water Path in Waterflood Operations

Injection water temperature at the injection wellhead is usually much lower than reservoir temperature. As it travels down the injection wellstring, the water cools the surrounding formations, and its temperature and pressure increase. If the water is saturated at surface conditions with salts whose solubility decreases with increasing temperatures (e.g. anydrite), scale may form along the wellstring.

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