NRAS Q61R

The finding of synchronous mutations is a rare occurrence suggesting for intratumoral heterogeneity (ITH) even in PTC. Patients with multiple mutations have a clinical worse prognosis, generally characterized by an aggressive thyroid cancer, which may influence the surgical treatment, chemotherapy, and BRAF V600E mutation-targeting therapy.

The presence of recurrent RAC1 mutations in undifferentiated melanoma is also notable as these alterations may contribute to mitogen-activated protein (MAP) kinase pathway targeted therapy resistance. Furthermore, the RAC1 alterations identified in this cohort have been shown to drive a melanocytic to mesenchymal switch in melanocytes, offering a possible explanation for the undifferentiated phenotype of these melanomas.

FNA rinses are a suitable source to perform molecular analysis after morphological evaluation maximizing diagnostic efficiency. Additionally, BRAF V600E is not the sole pathogenic alteration in thyroid cancer, so expanding tests to include other molecular alterations may enhance diagnostic utility using this available material.

Lox-stop-Lox NrasQ61R mice were crossed with Prox1-CreERT2 mice expressing tamoxifen-inducible Cre recombinase specifically in LECs...These results suggest that the NRAS p.Q61R variant in LECs plays a role in development of lymphatic anomalies. While this model does not directly reflect the human pathology of GLA and KLA, there are overlapping features, suggesting that further study of this model may help in studying GLA and KLA mechanisms.

Our studies show that the NRASQ61R mutation in endothelial cells induces Ang-2 expression in vitro and in vivo. In cultured human endothelial cells, NRASQ61R drives elevated Ang-2 through MAP kinase and mTOR-dependent signaling pathways.

This observation reveals a binding site that can potentially be exploited for development of inhibitors against mutant NRAS. Furthermore, the well-resolved catalytic site of this GTPase bound to native GTP provides insight into the stalled GTP hydrolysis observed for NRAS-Q61K.

Tumour thickness ≥ 4 mm, ulceration, the coexistence of regression and TILs, and positive BRAFV600E were risk factors for poor prognosis of CoM patients. Besides, expression level of BRAFV600E was positively correlated with the expression levels of PD-1 and PD-L1.

A subset (10.3%) of multifocal PTCs had discordant molecular drivers and 90.0% of them were a combination of BRAF-positive and kinase gene fusion-associated PTCs, mostly with different histologic subtypes. Half of the cases had nodal metastasis and 40% (2/5) of them showed simultaneous involvement by tumors with discordant molecular drivers. These findings highlight the clinical importance of identifying such cases given the potentially different management with specific targeted therapies.

Demographic details, tumor characteristics, and 10-year outcome data were also obtained.Ten cases with BRAF V600E mutations (11.6%) and five (5.49%) NRAS mutations (4 at Q61R, 1 at Q61K) were detected. No statistically significant differences were noted between groups for age, gender, depth of invasion, nodal status, or recurrence status (p ≥ 0.05).These findings suggest that the Irish population has a markedly lower incidence of BRAF and NRAS mutations in melanoma than those reported in other cohorts.

No recurrence or carcinoma development was observed in any of the IUP cases during the follow-up period. Thus, we confirmed the importance of RAS pathway activation in IUP pathogenesis, an association between RAS family gene mutations and IUP subtypes, and the spread patterns of IUP cells within the surface.

Twenty tested cases showed retained SMARCA4 expression. We conclude that ATCs express a number of divergent lineage markers that can cause diagnostic dilemmas, as they are also features of other tumors in the differential diagnosis of high-grade midline neck malignancies.

We found that all 23 CAAs showed diffuse and strong membranous RAS Q61R immunoreactivity (100% sensitivity), while none of the 8 OSCCs showed immunoreactivity (100% specificity). The data supports the use of RAS Q61R-specific rabbit monoclonal antibody for diagnostic IHC confirmation of CAA and ruling out OSCC in dogs.

We induced mice with 4-OH tamoxifen ± UV exposure to accelerate melanoma development...Our model allows studies of PDL1 signals in melanomagenesis and progression and distinguishes bona fide tumor cell-intrinsic PDL1 signals and influences on the TME. Conclusions Our novel model distinguishes bona-fide cell-intrinsic PDL1 signals from potential genetic PDL1KO compensation confounding effects, allows studies of earliest PDL1 signals in melanomagenesis and progression, helps understand if PDL1 affects NRAS-driven oncogenesis, and helps test immunotherapy and small molecule treatment effects.

Even focal expression of a melanocytic marker should cast doubt on a diagnosis of PDS and raise the possibility of de-differentiated melanoma, since therapy and outcomes are significantly different. Poster type: Poster Defense

P1/2, N=39, Completed, Gritstone bio, Inc. | Active, not recruiting --> Completed | Trial completion date: Dec 2023 --> Mar 2023 | Trial primary completion date: Dec 2023 --> Mar 2023

Unlike AID-Cre+/-mice, AIDCreERT2 +/- mice express Cre recombinase under the control of an AID promoter and tamoxifen. Mice carrying a combination of these traits developed clonal expansion of clonal CD138+ MM cells in the bone marrow and experienced MGUS and MM as they aged (100% of mice after 6 months of age)... Our newly generated third generation AEY-PK/V/QM mice with short latency and high penetrance are feasible for preclinical studies without the need of transplantation avoided potential Graft vs. Host Disease (GVHD) from different mice.

Subsequent selection via transplantation and bortezomib (Btz) treatment established transplantable t-Vk*MYC lines (e.g. t-Vk12653) that shows reduced response to Btz in vivo...Compared to Group A VQ and t-Vk12653 MM models, Group B VQ expresses additional hrMM and ultra hrMM features, including downregulation of Fam46c, expression of UAMS-70 and EMC-92 hrMM gene signatures and Amp1q-associated PBX1-FOXM1 gene signatures, upregulation of cancer growth pathways associated with functional hrMM, and de novo resistance to venetoclax in vitro and to Btz and anti-TIGIT immune checkpoint blockade in vivo... Our study provides a strong rational to develop Tra-based immunotherapies for treating RAS-driven hrMM and ultra hrMM.

Each OSUMMER cell line possesses distinct in vitro growth properties, trametinib sensitivity, mutational signatures, and predicted antigenicity. Analysis of OSUMMER allografts shows a correlation between strong, predicted antigenicity and poor tumor outgrowth. These data suggest that the OSUMMER lines will be a valuable tool for modeling the heterogeneous responses of human melanomas to targeted and immune-based therapies.

Conclusions Molecular screening in non-BRAF PTC patients is useful to identify patients harboring RET fusions who may benefit from targeted therapies. As other potentially actionable gene fusions are also found in these patients, routine implementation of NGS analysis warrants a comprehensive biomarker study.

The PFS and OS were not affected by NRAS mutational status in patients treated with anti-PD1-based ICI. Similar ORR was seen in NRASwt and NRASmut patients. Tumour PD-L1 expression did not correlate with NRAS mutational status.

Driver gene fusions were identified in 8.5% of PTCs and were clinically relevant given the emerging targeted kinase inhibitor therapy. Of the 1.6% of cases for which no driver alteration was detected, the specificity of drivers tested and tumor classification require further investigation.

Results The NGS analysis showed similar results for melanoma cell lines A375 and A2058, with SNV genomic alteration of BRAF (V600E) as relevant biomarker targeted by kinase inhibitors (binimetinib + encorafenib; cobimetinib + vemurafenib; dabrafenib; dabrafenib + trametinib), but also indicator of checkpoint inhibitors uses (atezolizumab; ipilimumab + nivolumab) in combinatorial therapies. Nevertheless, SK-MEL-2 cell line had similar immunophenotypic profile, although the genomic alterations were totally different. Discussion For establishing the appropriate therapeutic approach in melanoma cases, the personalized treatment should be envisioned, based on both next generation sequencing, surface markers expression, as well as microenvironment assessment.

Results The NGS analysis showed similar results for melanoma cell lines A375 and A2058, with SNV genomic alteration of BRAF (V600E) as relevant biomarker targeted by kinase inhibitors (binimetinib + encorafenib; cobimetinib + vemurafenib; dabrafenib; dabrafenib + trametinib), but also indicator of checkpoint inhibitors uses (atezolizumab; ipilimumab + nivolumab) in combinatorial therapies. Nevertheless, SK-MEL-2 cell line had similar immunophenotypic profile, although the genomic alterations were totally different. Discussion For establishing the appropriate therapeutic approach in melanoma cases, the personalized treatment should be envisioned, based on both next generation sequencing, surface markers expression, as well as microenvironment assessment.

This study aimed to explore the functional effects of NRAS Q61R overexpression in MM cell lines. The results showed that overexpression of NRAS Q61R negatively affects cell proliferation but increases cell migration and invasiveness. These findings suggest mechanisms by which NRAS Q61R may play a significant role in the progression and aggressiveness of MM.

In this cohort with population-based and real-world patients, no differences in patient characteristics or treatment modalities were seen between different RAS mt, except a higher frequency of right-colon primaries among KRAS mt compared with NRAS mt. KRAS -G12S conferred a worse OS compared with some other KRAS mt, whereas no other differences in OS were seen. It therefore seems as if different RAS mt behave quite similar.

NRAS mutated melanoma has been shown to respond to treatment with the MEK-inhibitor binimetinib, however the PFS of 2,8 months and the median OS of 11 months was not promising [1]. Three patients with high tumor load all benefitted from treatment with trametinib and showed a explicitly longer PFS than the published data. After progression on ICB we therefore recommend to consider MEK-inhibition for NRAS mutated melanoma in selected cases.

P2/3, N=8, Terminated, The Christie NHS Foundation Trust | N=1050 --> 8 | Trial completion date: Oct 2030 --> Jan 2023 | Recruiting --> Terminated | Trial primary completion date: Oct 2030 --> Jan 2023; Closed earlier than expected due to the need for a redesign to reflect the recent change in standard of care guidelines. New design will include these treatments.

We induced mice with 4-OH tamoxifen ± UV exposure to accelerate melanoma development...Transplanted 4.5 kJ/m2 UV-induced PDL1KO TNQ61R tumors were resistant to αPD1, αPDL1, αPDL2, and CD122-biased IL2 in WT mice vs. B16 melanomas, which are sensitive to biased IL2. Our model allows studies of PDL1 signals in melanomagenesis and progression and distinguishes bona fide cell-intrinsic PDL1 signals.

analysis for BRAFV600- and NRASQ61-mutant ctDNA on CSF using the Idylla® platform holds promise as a sensitive and specific complementary biomarker for the diagnosis of LMM, especially in cases with ambiguous imaging or CSF cytology results. The rapid (90 min) analysis of 1 ml of CSF, offering same day results, can be of important benefit, facilitating urgent treatment decisions.

In conclusion, our study revealed that secondary tumors arising from NS harbor known RAS hotspot mutations and additional genomic alterations, including putative driver mutations and PTCH1 copy-loss. These results could help to define the high-risk group for tumor development in patients with NS and provide evidence for prophylactic resection.

"Of 21 pts with paired plasma samples, 17 (81%) had ≥1 acquired genomic alteration. RTK alterations and secondary (2°) RAS alterations were most common; each occurred in 57% of pts (Table). KRAS amplification was the most common single alteration (43%)."

Regardless of the therapeutic effect of class I BRAF inhibitors such as vemurafenib, dabrafenib and encorafenib, melanoma patients with BRAF non-V600/RAS mutations remain limited response...The effect of PHI-501 on anchorage independent growth and cell proliferation compared to vemurafenib or belvarafenib (pan-RAF inhibitor) were tested in A375 (BRAFV600E), C8161 (BRAFG464E) and SK-MEL-2 (NRASQ61R) melanoma cell lines by soft agar assay, western blot and FACS analysis... PHI-501, a novel pan-RAF inhibitor, has potent oral anti-tumor activity. Melanoma cells harboring BRAF non-V600/NRAS or BRAF common V600E mutations exhibited significantly reduced proliferation, increased apoptosis and inhibited migration upon treatment with PHI-501. The results of this study suggest that PHI-501 has a potential to overcome the limited response in the treatment of melanoma, and warrant evaluation of PHI-501 as a single agent to treat both BRAF-and NRAS-mutated metastatic melanoma.

We therefore anticipate mechanistic analyses of how %VAF and drug timing can optimize counter-resistance therapies. Overall, our interim data suggest a significant percentage of metastatic BRAF-mutated melanoma patients may harbor pre-existing resistant subclones, and that early treatment with counter-resistance therapy can potentially delay resistance to targeted therapy.

P1/2, N=39, Active, not recruiting, Gritstone bio, Inc. | Recruiting --> Active, not recruiting | N=144 --> 39

P1/2, N=144, Recruiting, Gritstone bio, Inc. | Trial primary completion date: Dec 2022 --> Dec 2023

Afirma XA detected abnormalities in approximately one-third of Afirma GSC suspicious nodules, of which RAS mutations were the most common finding (68%). Two-thirds of cases labeled suspicious by Afirma GSC did not reveal gene mutations or fusions by Afirma XA testing, suggesting other unknown genetic alterations requiring further investigation.

In this post-2017 WHO classification cohort of 554 consecutive PTCs, BRAF V600E mutation is highly prevalent in 87% of the cases. RAS mutations account for only 1.1% of the cases and half of them are classified as encapsulated follicular variant of PTC. Kinase gene fusions are identified in 8.5% of the cases and are clinically relevant given the emerging targeted kinase inhibitor therapy.

XA improved risk stratification and identification of malignant thyroid disease with a very high ROM in GSC “suspicious” nodules. Although a negative XA result was associated with lower RoM in our cohort, a negative XA result should not be used as a “rule-out” test.