Fascin expression in skull base chordoma: correlation with tumor recurrence and dura erosion

Developmental gene expression in skull-base chordomas and chondrosarcomas

PURPOSE

 Chordomas are malignant tumors of the axial spine and skull base, and they are notorious for their poor treatment response. Differentiating these tumors from comparatively less malignant chondrosarcomas is crucial for treatment and prognostication. Both tumor types differ in their developmental origin. Chordomas are considered to be derived from notochordal remnants and chondrosarcomas from mesenchymal cells. Here, we evaluated the differential expression of developmental transcription factors in these skull base tumors.

METHODS

 Histopathologically-confirmed tumor biopsies were obtained from 12 chordoma and 7 chondrosarcoma patients. Following RNA extraction, samples were submitted to real-time quantitative PCR (RT-qPCR) for the evaluation of 32 evolutionary conserved genes that are known to associate with notochord, mesoderm, and axial spine development. Gene expression levels were normalized to housekeeping genes ACTB and RS27a.

RESULTS

 Fifteen genes were either exclusively expressed (n = 12) or overexpressed (n = 3; 2.21-4.43 fold increase) in chordoma, compared to chondrosarcoma. Brachyury and CD24 were highly and exclusively expressed in chordoma. Other novel genes exclusive to chordomas included chordin, HOXA5 and ACAN. Vice versa, ten genes were either exclusively expressed (n = 2) or overexpressed (n = 8; 0.01-0.66 fold increase) in chondrosarcoma, compared to chordoma.

CONCLUSION

 As chordoma patients demonstrate a worse prognosis compared to chondrosarcoma patients, the differential expression of chordin, HOXA5 and ACAN and CD24 could be relevant for the pathophysiology of chordomas and may have diagnostic and treatment value. Further study on role of these genes in tumorigenesis is therefore warranted.

Natural Growth Dynamics of Untreated Skull Base Chordomas In Vivo

OBJECTIVE

To study the natural growth dynamics of skull base chordomas.

METHODS

A retrospective study of skull base chordomas was performed. Patients with ≥2 preoperative magnetic resonance (MR) images and with pathologically confirmed chordomas were enrolled. All clinical data and MR images were studied.

RESULTS

Twenty-one patients with pathologically confirmed skull base chordomas were enrolled. The mean volume of the tumors at diagnosis was 19.9 ± 17.0 cm³, with a mean interval examination period of 22.4 ± 26.1 (range, 3-113) months. The mean tumor volume change was approximately 15.4 ± 16.3 cm³. The mean specific growth rate was 8% ± 9% per month, and the mean specific growth volume was 0.8 ± 0.7 cm³ per month. The tumor MR signal index grade, female gender, no dura mater breakthrough, endophytic type, small tumors, and soft tumor texture were related to a higher tumor growth rate (P < 0.05), and small tumors showed the greatest growth rate compared with the middle-sized and large tumors. Curve estimation was performed using a power function (R² = 0.545).

CONCLUSIONS

The skull base chordoma is a slow-growing tumor. The cases involving characteristics of female gender, endophytic type, small tumor size, and MR grade 3 showed a higher growth rate.

Giant petroclival primary intradural chordoma: case report and systematic review of the literature

Background Chordomas are rare, locally aggressive neoplasms thought to arise from notochordal remnants in the axial skeleton. Primary intradural chordomas are considered to be extremely rare. In this article a giant intradural petroclival chordoma is presented, and a synthesis of the available literature is performed to measure overall survival (OS) and recurrence-free survival (RFS) and to identify prognostic factors.

Methods A systematic Medline review yielded 47 patients with purely intradural tumors from 38 publications including 39 chordomas, 8 cases of ecchordosis physaliphora, and 1 case with features of both. The 5-year OS and RFS were calculated based on the Kaplan-Meier method. Risk factors for progression or mortality were analyzed using binomial logistic regression.

Results Maximal tumor diameter varied from 1.5 to 6.0 cm (mean: 3.2 cm). Tumors were located predominantly in the prepontine area (66.7%). Combined 5-year Kaplan-Meier OS and RFS were 77% ± 11% and 74% ± 11%, respectively. Incomplete surgical resection, larger tumor diameter, and an elevated Ki-67 index were statistically more frequent in cases of recurrence and mortality.

Conclusions Based on a systematic literature review, the behavior of primary intradural chordomas may be closer to typical chordomas than was previously thought.

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.