Abstract 3118
Background
Retinoblastoma (RB) is the most common pediatric intraocular neoplasm caused by the biallelic inactivation of the RB1 tumor suppressor gene. In 40% of cases, the development of RB is mediated by a germline mutation in one of the alleles of RB1. Patients with germline mutation develop bilateral tumor with penetrance of more than 90%. However, some families demonstrate cases of RB with low penetrance (unaffected carries) and variable expressivity (carries develop either bi- or uni- RB).
It is believed that the phenotypic manifestation of hereditary retinoblastoma depends on the functional type of the germinal mutation in the RB1. The molecular mechanisms underlying the variable phenotypic manifestation of the same mutation in different family members are currently explained by the parent-of-origin effect of RB1 mutation.
Methods
Using NGS of the RB1 we have analyzed DNA from blood of 331 unrelated patients with RB (226 patients with uni- RB and 105 with bi- RB). DNA samples of available family members were also examined for the presence of an identified mutation using Sanger sequencing.
Results
We identified 11 germline mutations in the RB1 that led to the RB with low penetrance and/or variable expressivity in 12 families. Among the identified mutations:, 25.0% - are missense mutations, 58.3% - are splice mutations and 16.7% - are frame shift mutations. In 91,7% of cases, probands inherited the mutant allele from their fathers, who were either clinically healthy carriers (7 families) or had the uni-/bilateral form of RB (3 families).Table: 1170P
Mutations | Carrier (Proband, P) | Form (uni, U; bi-lateral, B; no symptoms, -) |
---|---|---|
c.1364G>C; c.1573G>A; c.1981C>T; с.607 + 1G-T (2 families); c.45_76del; с.83del | P ♂ | U - |
c.861G>C | P ♀ | U - |
c.939G>A | P ♂ Grandfather Uncle | U - - U |
c.380 + 1G-A; с.1695 + 5G-T; c.1696-2A-G | P ♂ | B U |
Conclusions
The identification of mutations in the RB1 leading to the development of RB with low penetrance and variable expressivity, is necessary for adequate treatment and competent determination of the risk of developing the disease in other family members.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
State assignment of Ministry of Science and Higher Education of the Russian Federation.
Funding
The state assignment of Ministry of Science and Higher Education of the Russian Federation.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
4543 - Long-term real-world (RW) outcomes in patients with advanced melanoma (MEL) treated with ipilimumab (IPI) and non-IPI therapies: IMAGE study
Presenter: Stéphane Dalle
Session: Poster Display session 3
Resources:
Abstract
4523 - Prognostic Factors for efficacy of Ipilimumab used after AntiPD1 and/or BRAF+MEK inhibitors in Melanoma Patients: an Italian Melanoma Intergroup study
Presenter: Riccardo Marconcini
Session: Poster Display session 3
Resources:
Abstract
3632 - Rechallenge with combination ipilimumab and anti-PD-1 (IPI+PD1) in metastatic melanoma after acquired resistance to IPI+PD1 immunotherapy
Presenter: Adriana Hepner
Session: Poster Display session 3
Resources:
Abstract
3732 - Clinicopathologic characteristics of immune colitis in melanoma patients treated with combination ipilimumab and anti-PD1 (IPI+PD1) and PD1 monotherapy.
Presenter: Kazi Nahar
Session: Poster Display session 3
Resources:
Abstract
5005 - Real-world outcomes of ipilimumab plus nivolumab for advanced melanoma in the Netherlands
Presenter: Michiel van Zeijl
Session: Poster Display session 3
Resources:
Abstract
5524 - Utilization of Real-World Data to Assess the Effectiveness of Immune Checkpoint Inhibitors (ICIs) in Elderly Patients with Metastatic Melanoma
Presenter: D Scott Ernst
Session: Poster Display session 3
Resources:
Abstract
5884 - Tumor mutational burden and response to PD-1 inhibitors: an analysis of 89 cases of metastatic melanoma.
Presenter: Léa Dousset
Session: Poster Display session 3
Resources:
Abstract
3120 - Increase in S100B and LDH as early outcome predictors for non-responsiveness to anti-PD-1 monotherapy in advanced melanoma.
Presenter: Elisa Rozeman
Session: Poster Display session 3
Resources:
Abstract
2157 - Immune status defined by molecular information layers predicts response to pembrolizumab treatment in advanced melanoma
Presenter: Guillermo Prado-Vázquez
Session: Poster Display session 3
Resources:
Abstract
2553 - Interim analysis of a phase Ib study of cobimetinib plus atezolizumab in patients with advanced BRAFV600 wild type melanoma progressing on prior anti-PD-L1 therapy
Presenter: Shahneen Sandhu
Session: Poster Display session 3
Resources:
Abstract