Clinical, Genomic, and Pharmacological Study of MYCN-Amplified RB1 Wild-Type Metastatic Retinoblastoma

An uncommon subgroup of unilateral retinoblastomas with highly aggressive histological features, lacking aberrations in RB1 gene with high-level amplification of MYCN (MCYNamplRB1+/+) has only been described as intra-ocular cases treated with initial enucleation. Here, we present a comprehensive clinical, genomic, and pharmacological analysis of two cases of MCYNamplRB1+/+ with orbital and cervical lymph node involvement, but no central nervous system spread, rapidly progressing to fatal disease due to chemoresistance. Both patients showed in common MYCN high amplification and chromosome 16q and 17p loss. A somatic mutation in TP53, in homozygosis by LOH, and high chromosomal instability leading to aneuploidy was identified in the primary ocular tumor and sites of dissemination of one patient. High-throughput pharmacological screening was performed in a primary cell line derived from the lymph node dissemination of one case. This cell line showed resistance to broad spectrum chemotherapy consistent with the patient's poor response but sensitivity to the synergistic effects of panobinostat-bortezomib and carboplatin-panobinostat associations. From these cells we established a cell line derived xenograft model that closely recapitulated the tumor dissemination pattern of the patient and served to evaluate whether triple chemotherapy significantly prolonged survival of the animals. We report novel genomic alterations in two cases of metastatic MCYNamplRB1+/+ that may be associated with chemotherapy resistance and in vitro/in vivo models that serve as basis for tailoring therapy in these cases.

Immunoreactivity of the 14F7 Mab raised against N-Glycolyl GM3 Ganglioside in retinoblastoma tumours

INTRODUCTION

The identification of molecules expressed selectively on the surface of retinoblastoma cells would allow applying targeted therapies. The Ganglioside, N-Glycolyl-GM3 (NeuGc-GM3), is an attractive candidate, as it has been detected in other paediatric neuroectodermic tumours, and it is not expressed in human normal tissues. The 14F7 antibody recognizes specifically the ganglioside NeuGc-GM3.

PURPOSE

To characterize the expression of NeuGc-GM3 in retinoblastoma cell lines and in retinoblastoma tumours using the 14F7 monoclonal antibody.

METHODS

We studied WERI-Rb1 and Y79 cell lines, 24 retinoblastoma primary tumours from unilateral and bilateral cases and two bone marrow biopsies from metastatic retinoblastoma. Tumours were classified into three groups: non-invasive (n = 13), invasive (n = 9) and metastatic (n = 2). Three eyes enucleated because of non-tumoural conditions were used as controls. Cell lines and tumour sections were studied by immunohistochemistry using the 14F7 antibody. NeuGc-GM3 expression was evaluated by analysing the percentage of positive tumoural cells and the staining intensity. These parameters were analysed comparatively among the three groups.

RESULTS

Both retinoblastoma cell lines showed immunoreactivity to NeuGc-GM3 but WERI-Rb1 presented higher intensity than Y79. All the tumours studied showed strong immunoreactivity to NeuGc-GM3 with no significant differences among groups. In both bone marrow specimens, NeuGc-GM3 immunoreactivity was observed in retinoblastoma cells. In bilaterally enucleated cases, NeuGc-GM3 immunoreactivity was not altered before and after chemotherapy. Non-tumoural retinas were negative.

CONCLUSIONS

NeuGc-GM3 is highly expressed in retinoblastoma cell lines, tumours and metastatic cells to the bone marrow, and it is not detectable in control eyes. There were no significant differences in the immunoreactivity to 14F7 among tumours from different disease stages. Its immunoreactivity did not change after chemotherapy.

Combined high-dose intra-arterial and intrathecal chemotherapy for the treatment of a case of extraocular retinoblastoma

Patients with retinoblastoma and central nervous system (CNS) involvement are rarely curable with available treatments. We designed a high-dose intra-arterial regimen targeting the ophthalmic artery and chiasm combined with intrathecal chemotherapy to treat a 4-year-old patient with retinoblastoma metastasized to the CNS. After three cycles of this regimen, including carboplatin, melphalan, and intrathecal topotecan, a partial response of the orbital tumor mass and chiasmatic lesion, and complete response in the cerebrospinal fluid and bone marrow were achieved. This new treatment strategy may be explored as a treatment component for patients with overt extraocular retinoblastoma and CNS dissemination.

Is a diagnostic lumbar puncture indicated in intraocular retinoblastoma?

Background

Lumbar puncture (LP) is frequently performed in patients with advanced intraocular retinoblastoma. However, this may not be necessary in a significant proportion of patients.

Materials and Methods:

A file review of patients who were diagnosed with retinoblastoma over a 13-year-period was performed. Patients who underwent LP as part of staging were included in the study.

Results

The study included 223 patients. One-third had bilateral retinoblastoma. The grouping was C, D, and E in 4 (2.9%), 41 (29.9%), and 92 (67.2%) patients, respectively. The stage was 0, I, II, III, and IV in 14 (6.3), 123 (55.2%), 13 (5.8%), 70 (31.4%), and 3 (1.3%) patients, respectively. Eight (3.6%) patients had a positive cerebrospinal fluid (CSF) cytology. None of the patients with intraocular disease and 7 (10%) patients with extraocular disease had a positive CSF.

Conclusions

A diagnostic CSF is not indicated in patients with intraocular 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.

Case Report: Successful treatment of metastatic retinoblastoma with CNS involvement with anti-GD2 immunotherapy, intrathecal topotecan and reduced systemic chemotherapy

High-dose chemotherapy with autologous stem cell rescue has improved outcomes in patients with metastatic retinoblastoma (RB). Despite significant advances, acute and long-term side-effects, particularly in visually impaired and cancer-predisposed patients, underscore the need for additional treatment options. Monoclonal antibodies (mAbs) directed against the tumor-associated antigen GD2 are of considerable interest. Additional lines of RB research include tracking minimal disseminated disease (MDD) to permit timely intervention in patients with CNS metastasis. We present two cases of bilateral, metastatic RB, managed with the anti-GD2 mAb naxitamab following reduced intensity myeloablative chemotherapy and autologous stem cell transplant (ASCT) with intrathecal topotecan for MDD detected in the CSF. The patients remain disease-free 10 and 9 years after initial diagnosis. While additional studies are needed, the results suggest anti-GD2 mAbs and CNS-directed chemotherapy may improve long-term outcomes and reduce cytotoxicity for high-risk patients with RB.

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.

An Interesting Case of Post-enucleation Retinoblastoma Presenting With Distant Liver and Skeletal Metastases Detected on 18F-Fluorodeoxyglucose Positron Emission Tomography-Computed Tomography

Retinoblastomas are the most common primary ocular malignancies in the pediatric population. They are known to undergo metastasis to distant sites like the bone marrow, lymph nodes, and skeleton, but liver metastasis is rare. 18F-fluorodeoxyglucose positron emission tomography-computed tomography is an interesting imaging technique that allows for staging for disease metastasis and plays a crucial role in treatment planning and prognostication of retinoblastoma patients with suspected distant metastasis. The case report highlights this very fact by demonstrating the case of a one-year-old boy with retinoblastoma that had metastasized to the skull bones and even the liver.