Evaluation of 1p36 markers and clinical outcome in a skull base chordoma study

Immune microenvironment and immunotherapy for chordoma

Chordoma, as a rare, low-grade malignant tumor that tends to occur in the midline of the body, grows slowly but often severely invades surrounding tissues and bones. Due to the severe invasion and damage to the surrounding tissues, chordoma is difficult to be gross totally resected in surgery, and the progression of the residual tumor is often unavoidable. Besides, the tumor is insensitive to conventional radiotherapy and chemotherapy, thus finding effective treatment methods for chordoma is urgent. Nowadays, immunotherapy has made a series of breakthroughs and shown good therapeutic effects in kinds of tumors, which brings new insights into tumors without effective treatment strategies. With the deepening of research on immunotherapy, some studies focused on the immune microenvironment of chordoma have been published, most of them concentrated on the infiltration of immune cells, the expression of tumor-specific antigen or the immune checkpoint expression. On this basis, a series of immunotherapy studies of chordoma are under way, some of which have shown encouraging results. In this review, we reviewed the research about immune microenvironment and immunotherapy for chordoma, combined with the existing clinical trials data, hoping to clarify the frontiers and limitations of chordoma immune research, and provide reference for follow-up immunotherapy research on chordoma.

Prognostic molecular biomarkers in chordomas: A systematic review and identification of clinically usable biomarker panels

Introduction and objective

Despite the improvements in management and treatment of chordomas over time, the risk of disease recurrence remains high. Consequently, there is a push to develop effective systemic therapeutics for newly diagnosed and recurrent disease. In order to tailor treatment for individual chordoma patients and develop effective surveillance strategies, suitable clinical biomarkers need to be identified. The objective of this study was to systematically review all prognostic biomarkers for chordomas reported to date in order to classify them according to localization, study design and statistical analysis.

Methods

Using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we systematically reviewed published studies reporting biomarkers that correlated with clinical outcomes. We included time-to-event studies that evaluated biomarkers in skull base or spine chordomas. To be included in our review, the study must have analyzed the outcomes with univariate and/or multivariate methods (log-rank test or a Cox-regression model).

Results

We included 68 studies, of which only 5 were prospective studies. Overall, 103 biomarkers were analyzed in 3183 patients. According to FDA classification, 85 were molecular biomarkers (82.5%) mainly located in nucleus and cytoplasm (48% and 27%, respectively). Thirty-four studies analyzed biomarkers with Cox-regression model. Within these studies, 32 biomarkers (31%) and 22 biomarkers (21%) were independent prognostic factors for PFS and OS, respectively.

Conclusion

Our analysis identified a list of 13 biomarkers correlating with tumor control rates and survival. The future point will be gathering all these results to guide the clinical validation for a chordoma biomarker panel. Our identified biomarkers have strengths and weaknesses according to FDA’s guidelines, some are affordable, have a low-invasive collection method and can be easily measured in any health care setting (RDW and D-dimer), but others molecular biomarkers need specialized assay techniques (microRNAs, PD-1 pathway markers, CDKs and somatic chromosome deletions were more chordoma-specific). A focused list of biomarkers that correlate with local recurrence, metastatic spread and survival might be a cornerstone to determine the need of adjuvant therapies.

Genes Predicting Survival of Chordoma Patients

BACKGROUND

A chordoma is a slow-growing, invasive neoplasm in the neuraxis that is thought to arise from notochordal cells. At 10-year follow-up, the average survival rate is 50%, though individual prognosis varies substantially. We aimed to provide a comprehensive overview of the genes and proteins expressed in these tumors and their prognostic value to facilitate prognostication for patients with chordoma.

METHODS

A systematic search of clinical studies that investigated expressed factors related to chordoma survival was performed in PubMed. Data extracted included RNA and protein expression data and prognostic value (in terms of overall survival, progression-free survival, disease-free survival, and recurrence-free survival) from univariate and multivariate analyses.

RESULTS

This review included 78 original studies that collectively evaluated 134 expressed factors. Of these molecular factors, 96 by univariate analysis and 32 by multivariate analysis had a predictive value for patient survival. Of the molecular factors studied in multivariate analyses, 26 factors had a negative effect while 6 had a positive effect on patient survival.

CONCLUSIONS

Identification of molecular factors that are associated with survival contributes to better prognostication of patients with chordoma. Given the rarity of chordoma, often only univariate analyses can be performed. Robust multivariate analyses are scarcer but provide independently significant prognostic factors. The data presented in this review can aid in prognostication for the individual patient and facilitate the development of targeted therapies.

Endoscopic Endonasal Resection of Cranio-Cervical Junction Chordoma and Ventral Chiari Decompression: A Case Report

BACKGROUND

Chiari I malformations secondary to other causes represent a small subset of presenting symptomatic cases. Typically, the primary cause of the malformation is addressed first and results in resolution of the malformation and symptoms. However, in some cases, a patient may present with both a primary Chiari I malformation and another unrelated neurosurgical lesions.

OBJECTIVE

To present a unique case in which resection of a ventral tumor allowed for spontaneous resolution of a simultaneously noted dorsal Chiari I malformation.

METHODS

Pertinent data, including presenting symptoms, hospital course, surgical notes, preoperative images, and postoperative images, were collected using the electronic medical record.

RESULTS

We present a case of a 46-yr-old man with a Chiari I malformation in conjunction with a ventral cranio-cervical junction chordoma. Endoscopic endonasal resection of the chordoma and ventral foramen magnum decompression resulted in radiographic resolution of the Chiari malformation and resolution of his symptoms. Our report represents a rare case of ventral foramen magnum decompression as a treatment for Chiari I malformation.

CONCLUSION

It is felt that the chordoma mass effect was not the source of the Chiari I malformation. Thus, both ventral and dorsal decompressions of the posterior fossa may be considered for Chiari I decompression in select circumstances.

Molecular features and vulnerabilities of recurrent chordomas

Background

Tumor recurrence is one of the major challenges in clinical management of chordoma. Despite R0-resection, approximately 50% of chordomas recur within ten years after initial surgery. The underlying molecular processes are poorly understood resulting in the lack of associated therapeutic options. This is not least due to the absence of appropriate cell culture models of this orphan disease.

Methods

The intra-personal progression model cell lines U-CH11 and U-CH11R were compared using array comparative genomic hybridization, expression arrays, RNA-seq, and immunocytochemistry. Cell line origin was confirmed by short tandem repeat analysis. Inter-personal cell culture models (n = 6) were examined to validate whether the new model is representative. Cell viability after HOX/PBX complex inhibition with small peptides was determined by MTS assays.

Results

Using whole genome microarray analyses, striking differences in gene expression between primary and recurrent chordomas were identified. These expression differences were confirmed in the world’s first intra-personal model of chordoma relapse consisting of cell lines established from a primary (U-CH11) and the corresponding recurrent tumor (U-CH11R). Array comparative genomic hybridization and RNA-sequencing analyses revealed profound genetic similarities between both cell lines pointing to transcriptomic reprogramming as a key mechanism of chordoma progression. Network analysis of the recurrence specific genes highlighted HOX/PBX signaling as a common dysregulated event. Hence, HOX/PBX complexes were used as so far unknown therapeutic targets in recurrent chordomas. Treating chordoma cell lines with the complex formation inhibiting peptide HXR9 induced cFOS mediated apoptosis in all chordoma cell lines tested. This effect was significantly stronger in cell lines established from chordoma relapses.

Conclusion

Clearly differing gene expression patterns and vulnerabilities to HOX/PBX complex inhibition in highly therapy resistant chordoma relapses were identified using the first intra-personal loco-regional and further inter-personal chordoma progression models. For the first time, HOX/PBX interference was used to induce cell death in chordoma and might serve as the basic concept of an upcoming targeted therapy for chordomas of all progression stages.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13046-021-02037-y.

LncRNA-NONHSAT024778 promote the proliferation and invasion of chordoma cell by regulating miR-1290/Robo1 axis

Chordoma is a malignant bone tumor originating from the embryonic remnants of the notochord. lncRNAs act as competing endogenous RNAs (ceRNAs) and play a critical role in tumor pathology. However, the biological role of lncRNA-NONHSAT024778 and the underlying molecular mechanism in chordoma remains unknown. qRT-PCR was used to analyze the expression changes of NONHSAT024778 and miR-1290 in chordoma tissues and cell lines. Bioinformatics analysis and luciferase reporter assay were applied to detect the targeting binding effect between NONHSAT024778 and miR-1290, and between Robo1 and miR-1290. The effect of NONHSAT024778 on chordoma cell proliferation and invasion and its regulation of miR-1290 by acting as a ceRNA were also investigated. An increased NONHSAT024778 expression was correlated with a decreased miR-1290 level in chordoma tissues. NONHSAT024778 knockdown suppressed the proliferation and invasion of chordoma cells. miR-1290 restored expression rescued the carcinogenic function of NONHSAT024778. Bioinformatics analysis showed that NONHSAT024778 acted as ceRNA to regulate Robo1 via sponging miR-1290 in chordoma cells, thereby promoting chordoma cell malignant progression. In vivo results confirmed the anti-tumor effects of NONHSAT024778 knockdown activating miR-1290 to inhibit the oncogene Robo1. NONHSAT024778 is substantially overexpressed, whereas miR-1290 is decreased in chordoma tissue. NONHSAT024778-miR-1290-Robo1 axis plays a critical role in chordoma tumorigenesis and might be a potential predictive biomarker for the diagnosis and therapeutic target among patients with chordoma.

Chordoma: A Case Report and Review of Literature

Patient: Female, 68-year-old

Final Diagnosis: Chordoma

Symptoms: Hoarseness • neck pain • weakness

Medication: —

Clinical Procedure: —

Specialty: Oncology

Prospective validation of a molecular prognostication panel for clival chordoma

OBJECTIVE

There are currently no reliable means to predict the wide variability in behavior of clival chordoma so as to guide clinical decision-making and patient education. Furthermore, there is no method of predicting a tumor's response to radiation therapy.

METHODS

A molecular prognostication panel, consisting of fluorescence in situ hybridization (FISH) of the chromosomal loci 1p36 and 9p21, as well as immunohistochemistry for Ki-67, was prospectively evaluated in 105 clival chordoma samples from November 2007 to April 2016. The results were correlated with overall progression-free survival after surgery (PFSS), as well as progression-free survival after radiotherapy (PFSR).

RESULTS

Although Ki-67 and the percentages of tumor cells with 1q25 hyperploidy, 1p36 deletions, and homozygous 9p21 deletions were all found to be predictive of PFSS and PFSR in univariate analyses, only 1p36 deletions and homozygous 9p21 deletions were shown to be independently predictive in a multivariate analysis. Using a prognostication calculator formulated by a separate multivariate Cox model, two 1p36 deletion strata (0%-15% and > 15% deleted tumor cells) and three 9p21 homozygous deletion strata (0%-3%, 4%-24%, and ≥ 25% deleted tumor cells) accounted for a range of cumulative hazard ratios of 1 to 56.1 for PFSS and 1 to 75.6 for PFSR.

CONCLUSIONS

Homozygous 9p21 deletions and 1p36 deletions are independent prognostic factors in clival chordoma and can account for a wide spectrum of overall PFSS and PFSR. This panel can be used to guide management after resection of clival chordomas.

Genomic and transcriptomic characterization of skull base chordoma

Skull base chordoma is a primary rare malignant bone-origin tumor showing relatively slow growth pattern and locally destructive lesions, which can only be characterized by histologic components. There is no available prognostic or therapeutic biomarker to predict clinical outcome or treatment response and the molecular mechanisms underlying chordoma development still remain unexplored. Therefore, we sought out to identify novel somatic variations that are associated with chordoma progression and potentially employed as therapeutic targets. Thirteen skull base chordomas were subjected for whole-exome and/or whole-transcriptome sequencing. In process, we have identified chromosomal aberration in 1p, 7, 10, 13 and 17q, high frequency of functional germline SNP of the T gene, rs2305089 (P = 0.0038) and several recurrent alterations including MUC4, NBPF1, NPIPB15 mutations and novel gene fusion of SAMD5-SASH1 for the first time in skull base chordoma.

Immunophenotypic features of dedifferentiated skull base chordoma: An insight into the intratumoural heterogeneity

Chordomas are rare and low-grade malignant solid tumours, despite their histologically benign appearance, that arise in the bone from embryonic notochordal vestiges of the axial skeleton, a mesoderm-derived structure that is involved in the process of neurulation and embryonic development. Chordomas occurring in the skull base tend to arise in the basiocciput along the clivus. Three major morphological variants have been described (classical, chondroid, and atypical/dedifferentiated). The pathogenesis and molecular mechanisms involved in chordoma development remain uncertain. From a pathological standpoint, the microenvironment of a chordoma is heterogeneous, showing a dual epithelial-mesenchymal differentiation. These tumours are characterised by slow modality of biologic growth, local recurrence, low incidence of metastasis rates, and cancer stem cell (CSC) phenotype. The main molecular findings are connected with brachyury immunoexpression and activation of the downstream Akt and mTOR signalling pathways. The differentiation between typical and atypical chordomas is relevant because the tumoural microenvironment and prognosis are partially different. This review provides an insight into the recent and relevant concepts and histochemical markers expressed in chordomas, with special emphasis on dedifferentiated chordomas and their prognostic implications.

Low expression of miRNA-1290 associated with local invasion and recurrence in sacral chordoma

Chordoma is a rare, locally aggressive neoplasm of bone, usually with poor prognosis. The treatment for chordoma has been unsatisfactory for decades. MiRNAs were recently introduced into this field and provided new insights to the pathogenesis and pathophysiology of chordoma. However, molecular basis of chordoma remains ambiguous up to now. This research aims to discover novel miRNA molecules as potential biomarkers and therapeutic targets. We measured the expression of miRNA-1290 in chordoma tissues and fetal nucleus pulposus tissues by quantitative real-time PCR. Further, we analyzed its association with the clinical features as well as the prognosis of patients. The expression of miRNA-1290 in chordoma samples was significantly lower than fetal nucleus pulposus samples (P=0.026). Low expression of miRNA-1290 contributed to tumor invasion into surrounding muscle (P=0.013), while no obvious significance was identified between miRNA-1290 expression and patients' age, gender, tumor location and size (P>0.05). Log-rank test showed that low-level miRNA-1290 expression had a prominent impact on the patients' RFS (P=0.004). Conclusively, miRNA-1290 might be a valuable prognostic biomarker and efficient therapeutic target for sacral chordoma.

Genetic aberrations and molecular biology of skull base chordoma and chondrosarcoma

Chordomas and chondrosarcomas are two major malignant bone neoplasms located at the skull base. These tumors are rarely metastatic, but can be locally invasive and resistant to conventional chemotherapies and radiotherapies. Accordingly, therapeutic approaches for the treatment of these tumors can be difficult. Additionally, their location at the skull base makes them problematic. Although accurate diagnosis of these tumors is important because of their distinct prognoses, distinguishing between these tumor types is difficult due to overlapping radiological and histopathological findings. However, recent accumulation of molecular and genetic studies, including extracranial location analysis, has provided us clues for accurate diagnosis. In this report, we review the genetic aberrations and molecular biology of these two tumor types. Among the abundant genetic features of these tumors, brachyury immunohistochemistry and direct sequencing of IDH1/2 are simple and useful techniques that can be used to distinguish between these tumors. Although it is still unclear why these tumors, which have such distinct genetic backgrounds, show similar histopathological findings, comparison of their genetic backgrounds could provide essential information.

Skull base chordomas: clinical outcome in a consecutive series of 45 patients with long-term follow-up and evaluation of clinical and biological prognostic factors

OBJECTIVE

Skull base chordomas (SBCs) are rare dysembryogenetic invasive tumors with a variable tendency for recurrence. According to previous studies, the recurrence rate seems to be affected by both clinical variables and tumor biological features. The authors present the results of treatment of SBCs in a large series of patients and investigate the role of 1p36 chromosomal region loss of heterozygosity (LOH) as a prognostic factor.

METHODS

Between 1990 and 2011, 45 patients were treated for SBCs. The mean follow-up was 76 months (range 1–240 months). An LOH analysis was performed in 27 cases. Survival analysis was performed to determine clinical and biological parameters correlating with clinical outcome.

RESULTS

The 5- and 10-year overall survival rates were 67% and 57%, respectively. Five- and 10-year progression-free survival rates were 58% and 44%, respectively. Multivariate analysis showed that extent of resection, adjuvant radiation therapy, and absence of rhinopharynx invasion were positive independent predictors of overall survival. The latter 2 variables and a younger patient age were positive independent predictors of progression-free survival. Twenty-one patients showed 1p36 LOH. All events of recurrence and death clustered in the group of patients with 1p36 LOH; however, this biological marker was not statistically significant on multivariate analysis.

CONCLUSIONS

Resection is the treatment of choice in primary and recurrent SBC. Patient age, rhinopharynx invasion at diagnosis, extent of tumor removal, and postoperative radiation therapy influence SBC prognosis. Genetic analysis, even while showing interesting results, did not reveal 1p36 LOH as an independent predictor of clinical outcome.

Chordoma: an update on the pathophysiology and molecular mechanisms

Chordoma is a rare low-grade primary malignant skeletal tumor, which is presumed to derive from notochord remnants. The pathogenesis of chordoma has not been fully elucidated. However, recent advances in the molecular biology studies have identified brachyury underlying the initiation and progression of chordoma cells. More efforts have been made on accumulating evidence of the notochordal origin of chordoma, discovering signaling pathways and identifying crucial targets in chordomagenesis. In this review, we summarize the most recent research findings and focus on the pathophysiology and molecular mechanisms of chordoma.

Epigenetic deregulations in chordoma

Chordoma is a rare type of malignant bone tumour arising from remnant notochord and prognosis of patients with it remains poor as its molecular and genetic mechanisms are not well understood. Increasing evidence has demonstrated that epigenetic mechanisms (DNA methylation, histone modification and nucleosome remodelling), play a crucial role in the pathogenesis of many diseases. Aberrant epigenetic patterns are present in patients with chordoma, indicating a potential role for epigenetic mechanisms inthis malignancy. Furthermore, epigenetic alterations may provide novel biomarkers for diagnosis and prognosis as well as therapeutic targets for treatment. In this review, we discuss relevant epigenetic findings associated with chordoma, and their potential application for diagnosis, prognosis and treatment.

FAS/FASL are dysregulated in chordoma and their loss-of-function impairs zebrafish notochord formation

Chordoma is a rare malignant tumor that recapitulates the notochord phenotype and is thought to derive from notochord remnants not correctly regressed during development. Apoptosis is necessary for the proper notochord development in vertebrates, and the apoptotic pathway mediated by Fas and Fasl has been demonstrated to be involved in notochord cells regression. This study was conducted to investigate the expression of FAS/FASL pathway in a cohort of skull base chordomas and to analyze the role of fas/fasl homologs in zebrafish notochord formation. FAS/FASL expression was found to be dysregulated in chordoma leading to inactivation of the downstream Caspases in the samples analyzed. Both fas and fasl were specifically expressed in zebrafish notochord sorted cells. fas and fasl loss-of-function mainly resulted in larvae with notochord multi-cell-layer jumps organization, larger vacuolated notochord cells, defects in the peri-notochordal sheath structure and in vertebral mineralization. Interestingly, we observed the persistent expression of ntla and col2a1a, the zebrafish homologs of the human T gene and COL2A1 respectively, which are specifically up-regulated in chordoma. These results demonstrate for the first time the dysregulation of FAS/FASL in chordoma and their role in notochord formation in the zebrafish model, suggesting their possible implication in chordoma onset.

Molecular genetic study of novel biomarkers for early diagnosis of oral squamous cell carcinoma

Objectives: Early detection and treatment of an oral squamous cell carcinoma (OSCC) is critical because of its rapid growth, frequent lymph-node metastasis, and poor prognosis. However, no clinically-valuable methods of early diagnosis exist, and genetic analysis of OSCCs has yielded no biomarkers. Study Design: We investigated the expression of genes associated with inflammation in OSCCs via a quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) analysis of microarray data. Tumor and normal tissues from five patients with an OSCC were used for microarray analysis. Differentially-expressed genes, identified using permutation, local pooled error (LPE), t-tests, and significance analysis of microarrays (SAM), were selected as candidate genetic markers. Results: Two groups corresponding to tissue identity were evident, implying that their differentially-expressed genes represented biological differences between tissues. Fifteen genes were identified using the Student’s paired t-test (p<0.05) and the SAM, with a false discovery rate of less than 0.02. Based on gene expression, these 15 genes can be used to classify an OSCC. A genetic analysis of functional networks and ontologies, validated by using a qRT-PCR analysis of the tissue samples, identified four genes, ADAM15, CDC7, IL12RB2 and TNFRSF8, that demonstrated excellent concordance with the microarray data. Conclusions: Our study demonstrated that four genes (ADAM15, CDC7, IL12RB2 and TNFRSF8) had potential as novel biomarkers for the diagnosis and the treatment of an OSCC.

Key words:Biomarker, microarray, quantitative reverse transcription polymerase chain reaction, oral squamous cell carcinoma, gene expression profiling.

Chordoma: the entity

Chordomas are malignant tumors of the axial skeleton, characterized by their locally invasive and slow but aggressive growth. These neoplasms are presumed to be derived from notochordal remnants with a molecular alteration preceding their malignant transformation. As these tumors are most frequently observed on the skull base and sacrum, patients suffering from a chordoma present with debilitating neurological disease, and have an overall 5-year survival rate of 65%. Surgical resection with adjuvant radiotherapy is the first-choice treatment modality in these patients, since chordomas are resistant to conventional chemotherapy. Even so, management of chordomas can be challenging, as chordoma patients often present with recurrent disease. Recent advances in the understanding of the molecular events that contribute to the development of chordomas are promising; the most novel finding being the identification of brachyury in the disease process. Here we present an overview of the current paradigms and summarize relevant research findings.

Molecular and clinical risk factors for recurrence of skull base chordomas: gain on chromosome 2p, expression of brachyury, and lack of irradiation negatively correlate with patient prognosis

Chordomas are invasive tumors that develop from notochordal remnants and frequently occur in the skull base. The T gene and its product (brachyury) have recently been suggested to play an important role in chordoma progression. To date, few studies have investigated the relationship between the molecular/genetic characteristics of chordoma and patient prognosis. We analyzed 37 skull base chordomas for chromosomal copy number aberrations using comparative genomic hybridization, brachyury expression by immunohistochemistry, and T gene copy number by fluorescence in situ hybridization. The results of these molecular analyses and clinical parameters were compared with the patients' clinical courses. Univariate analyses using the log-rank test demonstrated that losses on chromosome 1p and gains on 1q and 2p were negatively correlated with progression-free survival, as were factors such as female sex, partial tumor removal, lack of postoperative irradiation, and high MIB-1 index. Expression of brachyury and copy number gain of the T gene were also significantly associated with shorter progression-free survival. Multivariate analysis using the Cox hazards model showed that lack of irradiation, gain on chromosome 2p, and expression of brachyury were independently associated with a poor prognosis. Our results suggest that brachyury-negative chordomas arebiologically distinct from brachyury-positive chordomas and that T/brachyury might be an appropriate molecular therapeutic target for chordoma.

High-resolution whole-genome analysis of skull base chordomas implicates FHIT loss in chordoma pathogenesis

Chordoma is a rare tumor arising in the sacrum, clivus, or vertebrae. It is often not completely resectable and shows a high incidence of recurrence and progression with shortened patient survival and impaired quality of life. Chemotherapeutic options are limited to investigational therapies at present. Therefore, adjuvant therapy for control of tumor recurrence and progression is of great interest, especially in skull base lesions where complete tumor resection is often not possible because of the proximity of cranial nerves. To understand the extent of genetic instability and associated chromosomal and gene losses or gains in skull base chordoma, we undertook whole-genome single-nucleotide polymorphism microarray analysis of flash frozen surgical chordoma specimens, 21 from the clivus and 1 from C1 to C2 vertebrae. We confirm the presence of a deletion at 9p involving CDKN2A, CDKN2B, and MTAP but at a much lower rate (22%) than previously reported for sacral chordoma. At a similar frequency (21%), we found aneuploidy of chromosome 3. Tissue microarray immunohistochemistry demonstrated absent or reduced fragile histidine triad (FHIT) protein expression in 98% of sacral chordomas and 67%of skull base chordomas. Our data suggest that chromosome 3 aneuploidy and epigenetic regulation of FHIT contribute to loss of the FHIT tumor suppressor in chordoma. The finding that FHIT is lost in a majority of chordomas provides new insight into chordoma pathogenesis and points to a potential new therapeutic target for this challenging neoplasm.

Systemic therapy options for unresectable and metastatic chordomas

Chordoma is an exceedingly rare tumor, marked by a slow growth rate. Surgery is the treatment of choice, but the most frequent sites of origin (spine and skull base) make treatment of primary disease challenging. Local relapses affect more than 50% of cases, with a minority of patients being cured by further surgery. Furthermore, metastases occur in at least 20% of patients. For residual or recurrent disease, high-dose radiation therapy may be indicated. Radiation therapy is currently the preferred local treatment when surgery is problematic, exploiting most recent techniques, including proton beams and carbon ions. However, systemic therapy is needed in patients non-amenable to surgery and/or radiation therapy. We reviewed systemic treatments currently available, and targets possibly druggable in the future in this orphan disease.

The biological basis for modern treatment of chordoma

Chordomas are rare malignant tumors arising in bone of the spheno-occiput, sacrum, and vertebral column which can cause neurological deficit. Current management of chordoma involves safe resection followed by radiation therapy. However, surgical resection is often subtotal and chordoma often recurs despite optimal therapy. Despite years of effort, effective adjuvant therapy for denovo, recurrent and metastatic chordoma are absent and 5-year survival is at best 65%. While no chemotherapeutic agent has been demonstrated to be effective against chordoma in vivo, a greater understanding of the genetics and molecular biology of chordoma is opening up avenues of investigation towards the rational development of targeted therapies. Although enthusiasm for the use of already established or new investigational agents will increase with greater understanding of chordoma biology, laboratory studies of these agents are important prior to incorporation into clinical human trials. The authors review the current state of knowledge regarding chordoma and offer insight into potential new therapies for this rare and challenging tumor.

The prognostic value of Ki-67, p53, epidermal growth factor receptor, 1p36, 9p21, 10q23, and 17p13 in skull base chordomas

CONTEXT

Skull base chordomas are rare, locally aggressive, notochord-derived neoplasms for which prognostically relevant biomarkers are not well established.

OBJECTIVE

To evaluate whether newly discovered molecular alterations in chordomas have prognostic significance similar to what has been described regarding Ki-67 proliferation index.

DESIGN

We conducted a retrospective study of 28 cases of primary clival chordomas.

RESULTS

Ki-67 proliferation index 5% or more, p53 accumulation, and epidermal growth factor receptor expression were seen in 32%, 44%, and 8% of chordomas, respectively. 1p loss of heterozygosity (LOH) and/or 1p36 hemizygous deletion was seen in 30% of tumors, while 9p LOH and/or 9p21 homozygous deletion was seen in 21% of cases. Loss of heterozygosity at 10q23 and 17p13 were identified in 57% and 52% of cases, respectively. Ki-67 proliferation index 5% or more and 9p LOH were significantly associated with a shorter overall survival, while homozygous deletion at 9p21 via fluorescence in situ hybridization approached significance. No correlation with survival was found for p53 or epidermal growth factor receptor expression, 1p36 hemizygous deletion, or LOH at 1p, 10q23, or 17p13.

CONCLUSIONS

Chordomas with elevated Ki-67 proliferation index or deletion at 9p21 may be at risk for a more aggressive clinical course and shorter survival. These biomarkers may thus be used to improve therapeutic stratification.

The prognostic value of Ki-67, p53, epidermal growth factor receptor, 1p36, 9p21, 10q23, and 17p13 in skull base chordomas

CONTEXT

Skull base chordomas are rare, locally aggressive, notochord-derived neoplasms for which prognostically relevant biomarkers are not well established.

OBJECTIVE

To evaluate whether newly discovered molecular alterations in chordomas have prognostic significance similar to what has been described regarding Ki-67 proliferation index.

DESIGN

We conducted a retrospective study of 28 cases of primary clival chordomas.

RESULTS

Ki-67 proliferation index 5% or more, p53 accumulation, and epidermal growth factor receptor expression were seen in 32%, 44%, and 8% of chordomas, respectively. 1p loss of heterozygosity (LOH) and/or 1p36 hemizygous deletion was seen in 30% of tumors, while 9p LOH and/or 9p21 homozygous deletion was seen in 21% of cases. Loss of heterozygosity at 10q23 and 17p13 were identified in 57% and 52% of cases, respectively. Ki-67 proliferation index 5% or more and 9p LOH were significantly associated with a shorter overall survival, while homozygous deletion at 9p21 via fluorescence in situ hybridization approached significance. No correlation with survival was found for p53 or epidermal growth factor receptor expression, 1p36 hemizygous deletion, or LOH at 1p, 10q23, or 17p13.

CONCLUSIONS

Chordomas with elevated Ki-67 proliferation index or deletion at 9p21 may be at risk for a more aggressive clinical course and shorter survival. These biomarkers may thus be used to improve therapeutic stratification.