Transcriptional analyses of adult and pediatric adamantinomatous craniopharyngioma reveals similar expression signatures regarding potential therapeutic targets

Genomic drivers in craniopharyngiomas: Analysis of the AACR project GENIE database

PURPOSE

Craniopharyngiomas are rare tumors originating in the sellar region, with limited information on their somatic mutational landscape. In this study, we utilized a publicly available genomic database to profile the somatic mutational landscape of craniopharyngioma patients and interrogate differences based on histologic subtype.

METHODS

We utilized the American Association for Cancer Research (AACR) Project Genomics Evidence Neoplasia Information Exchange (GENIE)® database accessed from cBioPortal (v13.1-public) to query all patients with craniopharyngiomas.

RESULTS

Of the 336 patients with sellar tumors, 51 (15.2%) had craniopharyngiomas. Of these 51 patients, 42 (82.4%) were adamantinomatous subtype and 9 (17.6%) were papillary subtype. In this cohort, 32 (62.7%) patients were pediatric, while 19 (37.3%) were adult. The top mutations in the cohort were: CTNNB1 (n = 37; 73%), BRAF (n = 7; 14%), ARID1B (n = 5; 10%), KMT2D (n = 4; 8%), FANCA (n = 4; 8%), ATM (n = 4; 8%), and TERT (n = 3; 8%). Of the 37 patients with CTNNB1 mutations, 8 (21.6%) had S33X, 9 (24.3%) had S37X, 7 (18.9%) had T41X, and 5 (13.5%) had D32X. In this cohort, CTNNB1 mutations tended to co-occur with ATM (n = 4; 10.8%), KMT2C (n = 4; 10.8%), TERT (n = 3; 8.1%), BLM (n = 3; 8.1%), and ERBB2/3 (n = 3; 8.1%), suggesting CTNNB1 mutations tended to co-occur with mutations in genes important in cell growth and survival, chromatin accessibility, and DNA damage response pathways.

CONCLUSIONS

CTNNB1 mutations account for a large proportion of somatic mutations in craniopharyngiomas. Identification of specific point mutations and secondary drivers may advance development of novel craniopharyngioma preclinical models for targeted therapy testing.

Multi-omics analysis of adamantinomatous craniopharyngiomas reveals distinct molecular subgroups with prognostic and treatment response significance

BACKGROUND

Adamantinomatous craniopharyngioma (ACP) is the commonest pediatric sellar tumor. No effective drug is available and interpatient heterogeneity is prominent. This study aimed to identify distinct molecular subgroups of ACP based on the multi-omics profiles, imaging findings, and histological features, in order to predict the response to anti-inflammatory treatment and immunotherapies.

METHODS

Totally 142 Chinese cases diagnosed with craniopharyngiomas were profiled, including 119 ACPs and 23 papillary craniopharyngiomas. Whole-exome sequencing (151 tumors, including recurrent ones), RNA sequencing (84 tumors), and DNA methylome profiling (95 tumors) were performed. Consensus clustering and non-negative matrix factorization were used for subgrouping, and Cox regression were utilized for prognostic evaluation, respectively.

RESULTS

Three distinct molecular subgroups were identified: WNT, ImA, and ImB. The WNT subgroup showed higher Wnt/β-catenin pathway activity, with a greater number of epithelial cells and more predominantly solid tumors. The ImA and ImB subgroups had activated inflammatory and interferon response pathways, with enhanced immune cell infiltration and more predominantly cystic tumors. Mitogen-activated protein kinases (MEK/MAPK) signaling was activated only in ImA samples, while IL-6 and epithelial-mesenchymal transition biomarkers were highly expressed in the ImB group, mostly consisting of children. The degree of astrogliosis was significantly elevated in the ImA group, with severe finger-like protrusions at the invasive front of the tumor. The molecular subgrouping was an independent prognostic factor, with the WNT group having longer event-free survival than ImB (Cox, P = 0.04). ImA/ImB cases were more likely to respond to immune checkpoint blockade (ICB) therapy than the WNT group ( P <0.01). In the preliminary screening of subtyping markers, CD38 was significantly downregulated in WNT compared with ImA and ImB ( P = 0.01).

CONCLUSIONS

ACP comprises three molecular subtypes with distinct imaging and histological features. The prognosis of the WNT type is better than that of the ImB group, which is more likely to benefit from the ICB treatment.

The molecular pathogenesis of craniopharyngiomas

Research from the last 20 years has provided important insights into the molecular pathogenesis of craniopharyngiomas (CPs). Besides the well-known clinical and histological differences between the subtypes of CPs, adamantinomatous (ACP) and papillary (PCP) craniopharyngiomas, other molecular differences have been identified, further elucidating pathways related to the origin and development of such tumors. The present minireview assesses current knowledge on embryogenesis and the genetic, epigenetic, transcriptomic, and signaling pathways involved in the ACP and PCP subtypes, revealing the similarities and differences in their profiles. ACP and PCP subtypes can be identified by the presence of mutations in CTNNB1 and BRAF genes, with prevalence around 60% and 90%, respectively. Therefore, β-catenin accumulates in the nucleus-cytoplasm of cell clusters in ACPs and, in PCPs, cell immunostaining with specific antibody against the V600E-mutated protein can be seen. Distinct patterns of DNA methylation further differentiate ACPs and PCPs. In addition, research on genetic and epigenetic changes and tumor microenvironment specificities have further clarified the development and progression of the disease. No relevant transcriptional differences in ACPs have emerged between children and adults. In conclusion, ACPs and PCPs present diverse genetic signatures and each subtype is associated with specific signaling pathways. A better understanding of the pathways related to the growth of such tumors is paramount for the development of novel targeted therapeutic agents.

Craniopharyngioma involving the anterior, middle, and posterior cranial fossa in adults: A case report

Craniopharyngioma (CP) is a rare benign tumor that develops from the residual epithelial cells of the craniopharynx, accounting for < 5% of intracranial tumors. It is common for CPs to grow in the sellar/parasellar region and extend suprasellar. The pathology classifies CPs into adamantinomatous craniopharyngiomas (ACP) and papillary craniopharyngiomas (PCP). The PCP is mainly solid and occurs only in adults. ACP is predominantly cystic and more common in childhood and adolescent. Multilocular cystic ACP involving the anterior, middle, and posterior cranial fossa is rare in adults. Here, we report a case of a 46-year-old adult male patient who presented with recurrent headaches for 1 year with choking and hoarseness. Computed tomography (CT) and magnetic resonance imaging (MRI) revealed multiple cystic masses in the anterior, middle, and posterior cranial fossa. Initial hypotheses included the following: CP, colloid cyst, enterogenous cyst, epidermoid cyst, and dermoid cyst. Subsequently, the patient underwent surgery and postoperative histopathology diagnosed ACP. Adults with ACP involving the anterior, middle, and posterior cranial fossae are uncommon. This is a rare condition that radiologists should be aware of.

Adamantinomatous craniopharyngioma associated with a compromised blood–brain barrier: patient series

BACKGROUND

Adamantinomatous craniopharyngioma (ACP) is a highly morbid adult and pediatric brain tumor derived from epithelial remnants of the craniopharyngeal canal (Rathke’s pouch), which gives rise to the anterior pituitary gland. Standard therapy includes maximal safe resection with or without radiation therapy. Systemic antitumor therapy remains elusive. Immune-related paracrine signaling involving the interleukin-6 receptor (IL-6R) may contribute to ACP pathogenesis. Tocilizumab, a recombinant humanized monoclonal antibody against IL-6R, is approved by the US Food and Drug Administration but does not cross an intact blood–brain barrier.

OBSERVATIONS

In a phase 0 trial design, a single dose of tocilizumab was delivered intravenously before clinically indicated surgical intervention in 3 children with ACP. The presence of tocilizumab was assayed in plasma, tumor tissue, tumor cyst fluid, and cerebrospinal fluid (n = 1) using a novel enzyme-linked immunosorbent assay. Tocilizumab reached ACP tumor tissue and/or cyst fluid after one systemic dose in every patient.

LESSONS

This finding helps explain extant data that indicate tocilizumab may contribute to ACP therapy. It further indicates that ACP does not reside behind an intact blood–brain barrier, dramatically broadening the range of potential antitumor therapies against this tumor. This has substantial implications for the design of future clinical trials for novel therapies against ACP in both children and adults.