Immunohistochemical expression of TFF1 is a marker of poor prognosis in retinoblastoma

INTRODUCTION

The risk of relapse in retinoblastoma is currently determined by the presence of high-risk histopathologic factors in the enucleated eye. However, the probability of developing metastatic disease is heterogeneous among these patients. Evaluating a biological marker to identify high-risk patients could be useful in clinical setting. This study aims to evaluate whether the expression of TFF1, a surrogate for subtype 2 retinoblastoma, is a prognostic marker for relapse and death.

METHODS

This multicenter cohort study included 273 patients, 48 of whom had extraocular disease. Immunohistochemical staining were performed for CRX, ARR3, TFF1, and Ki67. Tumors were classified as histological subtype 1 (HS1) if they had low or no expression of TFF1 (quick score (QS) ≤ 50) and as histological subtype 2 (HS2) if they expressed TFF1 diffusely (QS > 50). We studied the association between HS classification and outcome.

RESULTS

Of 273 patients, 35.9% were classified as HS1, 59.3% as HS2 and 4.8% were not evaluable. In multivariate analysis, patients with HS2 tumors had a higher probability of relapse and death than those with HS1 (p < .0001 and p = .00020, respectively). We identified a higher-risk subgroup among HS2 tumors, presenting non-mutually exclusive expression of ARR3 and TFF1 and had an increased risk of relapse and death compared with tumors that displayed mutually exclusive expression (p = .012 and p = .027, respectively).

CONCLUSIONS

Expression of TFF1, especially when it is not-mutually exclusive with ARR3, is an independent significant marker of poor outcome in retinoblastoma.

Establishment and Comprehensive Characterization of a Novel Preclinical Platform of Metastatic Retinoblastoma for Therapeutic Developments

Purpose

Although there have been improvements in the management of metastatic retinoblastoma, most patients do not survive, and all patients suffer from multiple short- and long-term treatment toxicities. Reliable and informative models to assist clinicians are needed. Thus we developed and comprehensively characterized a novel preclinical platform of primary cell cultures and xenograft models of metastatic retinoblastoma to provide insights into the molecular biology underlying metastases and to perform drug screening for the identification of hit candidates with the highest potential for clinical translation.

Methods

Orbital tumor, bone marrow, cerebrospinal fluid, and lymph node tumor infiltration specimens were obtained from seven patients with metastatic retinoblastoma at diagnosis, disease progression, or relapse. Tumor specimens were engrafted in immunodeficient animals, and primary cell lines were established. Genomic, immunohistochemical/immunocytochemical, and pharmacological analysis were performed.

Results

We successfully established five primary cell lines: two derived from leptomeningeal, two from orbital, and one from lymph node tumor dissemination. After the intravitreal or intraventricular inoculation of these cells, we established cell-derived xenograft models. Both primary cell lines and xenografts accurately retained the histological and genomic features of the tumors from which they were derived and faithfully recapitulated the dissemination patterns and pharmacological sensitivity observed in the matched patients.

Conclusions

Ours is an innovative and thoroughly characterized preclinical platform of metastatic retinoblastoma developed for the understanding of tumor biology of this highly aggressive tumor and has the potential to identify drug candidates to treat patients who currently lack effective treatment options.

Abstract 2500: Metastatic retinoblastoma exhibit MYCN alterations, recurrent CNAs and hypomethylation as molecular characteristics of aggressive disease

Retinoblastoma is a rare pediatric malignancy but the most frequent tumor of the eye. Metastatic disease is the most common cause of disease-related death and is rare in high-income countries. Therefore, little is known about the genomics, transcriptomics and methylomics of extraocular retinoblastoma. Here we present a series of extraocular retinoblastoma cases analyzed at DNA, RNA and methylation level to elucidate the landscape of the metastatic disease. These samples were analyzed by OncoScan CNV, CytoScan HD or whole-exome sequencing, depending on sample availability, for CNA (clonal and subclonal) and mutation analysis; RNAseq for fusion and expression data, and Infinium MethylationEPIC assay for methylation examination. Hierarchical clustering and subtype classification was performed using previously published expression and methylation signatures. Cell cultures were successfully established for 4 tumor specimens. In vitro pharmacological sensitivity of those cell cultures was determined by MTT assay. In total, 11 patients and 14 samples were studied (55% male, 64% unilateral). One patient was RB+/+ and harbored a MYCN amplification. Dissemination sites included orbit (n=8), systemic (n=3), and central nervous system (n=5). Median age at diagnosis was 27 months (5-48); 36% were already metastatic. All samples were classified as subtype 2 retinoblastoma according to Liu et. al., 2021, both at the expression and methylation level. Among recurrent CNAs in all samples, common retinoblastoma alterations were observed: 1q (86%), 2p (71%, 29% MYCN amplified), 6p (93%) gains and 16q (64%) loss. Other less frequent alterations such as 17q gain (21%) and 11q (43%) and 19q (29%) loss were found. MYCN pathway alteration was the most outstanding feature, evidenced by frequent gains/amplification on that gene and in gene-expression clustering based on MYCN expression signatures. Global hypomethylation was also observed when comparing metastatic to intraocular samples and it was consistent with the general gene overexpression seen in metastatic samples. Metastasis-derived in vitro cultures treated either with melphalan, topotecan, idarubicin, doxorubicin or carboplatin showed various degrees of sensitivity (i.e. EC50 in the nM to mM range), with no clear association to MYCN overexpression. In conclusion, even considering the caveats regarding our current sample size, we could detect the alteration of the MYCN pathway as a distinct characteristic of extraocular retinoblastoma. Global hypomethylation has been related to the activation of oncogenic drivers and is consistent with metastatic behavior. These results suggest a pattern of molecular features that may have been selected during tumor evolution. Our results do not support a straightforward relationship between MYCN activation and resistance to therapy.

Citation Format: Daiana Ganiewich, Santiago Zugbi, Rosario Aschero, Daniela Ottaviani, María B. Cancela, Fabiana Lubieniecki, Claudia Sampor, Cinzia Lavarino, François Radvanyi, Guillermo L. Chantada, Paula S. Schaiquevich, Andrea S. Llera. Metastatic retinoblastoma exhibit MYCN alterations, recurrent CNAs and hypomethylation as molecular characteristics of aggressive disease [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 2500.

Recurrent Somatic Chromosomal Abnormalities in Relapsed Extraocular Retinoblastoma

Simple Summary

Relapse outside the eye of retinoblastoma (the most common eye cancer in children) is an uncommon event in developed countries, however it is the main cause of death in patients with retinoblastoma worldwide. The genomic features of this population are not known. We studied 23 cases from four countries and found a characteristic pattern in chromosomal copy number alterations that could help guide future clinical management of these patients.

Abstract

Most reports about copy number alterations (CNA) in retinoblastoma relate to patients with intraocular disease and features of children with extraocular relapse remain unknown, so we aimed to describe the CNA in this population. We evaluated 23 patients and 27 specimens from 4 centers. Seventeen cases had extraocular relapse after initial enucleation and six cases after an initial preservation attempt. We performed an analysis of CNA and BCOR gene alteration by SNP array (Single Nucleotide Polymorfism array), whole-exome sequencing, IMPACT panel and CGH array (Array-based comparative genomic hybridization). All cases presented CNA at a higher prevalence than those reported in previously published studies for intraocular cases. CNA previously reported for intraocular retinoblastoma were found at a high frequency in our cohort: gains in 1q (69.5%), 2p (60.9%) and 6p (86.9%), and 16q loss (78.2%). Other, previously less-recognized, CNA were found including loss of 11q (34.8%), gain of 17q (56.5%), loss of 19q (30.4%) and BCOR alterations were present in 72.7% of our cases. A high number of CNA including 11q deletions, 17q gains, 19q loss, and BCOR alterations, are more common in extraocular retinoblastoma. Identification of these features may be correlated with a more aggressive tumor warranting consideration for patient management.

Genomic and Transcriptomic Tumor Heterogeneity in Bilateral Retinoblastoma

Importance

Comprehensive understanding of the genomic and gene-expression differences between retinoblastoma tumors from patients with bilateral disease may help to characterize risk and optimize treatment according to individual tumor characteristics.

Objective

To compare the genomic features between each eye and a specimen from an orbital relapse in patients with bilateral retinoblastoma.

Design, Setting, and Participants

In this case, 2 patients with retinoblastoma underwent upfront bilateral enucleation. Tumor samples were subjected to genomic and gene-expression analysis. Primary cell cultures were established from both of the tumors of 1 patient and were used for gene-expression studies.

Main Outcomes and Measures

Whole-exome sequencing was performed on an Illumina platform for fresh tumor samples and DNA arrays (CytoScan or OncoScan) were used for paraffin-embedded samples and cell lines. Gene-expression analysis was performed using Agilent microarrays. Germinal and somatic alterations, copy number alterations, and differential gene expression were assessed.

Results

After initial bilateral enucleation, patient 1 showed massive choroidal and laminar optic nerve infiltration, while patient 2 showed choroidal and laminar optic nerve invasion. Patient 1 developed left-eye orbital recurrence and bone marrow metastasis less than 1 year after enucleation. Both ocular tumors showed gains on 1q and 6p but presented other distinct genomic alterations, including an additional gain in 2p harboring the N-myc proto-oncogene (MYCN) in the left tumor and orbital recurrence. Similar copy number alterations between the orbital recurrence and the left eye supported the origin of the relapse, with an additional 11q loss only detected in the orbital relapse. Specimens from patient 2 showed common copy number gains and losses, but further evolution rendered a 2p gain spanning MYCN in the left tumor. For this patient, microarray expression analysis showed differential expression of the MYCN and the forkhead box protein G1 (FOXG1) gene pathways between the left and right tumors.

Conclusions and Relevance

Differential genomic and gene expression features were observed between tumors in 2 patients with bilateral disease, confirming intereye heterogeneity that might be considered if targeted therapies are used in such patients. Chromosomal alteration profile supported the origin of the orbital recurrence from the homolateral eye in 1 patient. Loss in chromosome 11q may have been associated with extraocular relapse in this patient.