Immunohistochemical expression of receptor tyrosine kinase PDGFR-α, c-Met, and EGFR in skull base chordoma.

Chordomas are rare, locally aggressive malignancies that often exhibit an insidious natural history and are difficult to eradicate. Surgery and radiotherapy are the treatment mainstays of chordoma, but the chance of local recurrence remains high. Reports of receptor tyrosine kinase (RTK) expression in chordoma suggest that these tumors may respond to kinase inhibitor therapy. Currently, there are no effective chemotherapeutic protocols for chordoma. A tissue microarray containing 74 tumor specimens from primary chordoma patients and 71 from their recurrent tumors for a total of 145 tumor specimens was immunohistochemically analyzed for expression of a number of proteins involved in signal transduction from RTKs. Platelet-derived growth factor receptor-α (PDGFR-α), epidermal growth factor receptor (EGFR), c-Met, and CD-34 were detected in 100, 92, 100, and 59% of cases, respectively. PDGFR-α and c-Met staining was of moderate to strong intensity in all cases. In contrast, total EGFR staining was variable; weak staining was detected in 10 cases. Our results contribute to the understanding of the expression of RTKs in skull base chordomas and support the development of targeted therapies that inhibit RTKs, which may have a synergistic effect for chemotherapy in patients. There were statistically significant correlations between the expression of PDGFR-α, c-Met, and EGFR and disease-free survival. The results nonetheless suggest that chordomas may respond to RTK inhibitors or modulators of other downstream signaling.

The influence of skull base chordoma on lower urinary tract symptoms.

OBJECTIVE: To provide the first insights into the potential role of skull base chordoma, which causes brainstem compression in and around Barrington's nucleus and its effect on the micturition center. Chordoma is a rare malignant bone tumor that originates from the remnants of the embryonic notochord, which normally forms and dissolves during early fetal development. Although it is a slowly growing tumor, it displays local invasive growth. METHODS: Urodynamic testing of 22 symptomatic patients was performed. All women and men with skull base chordoma treated in 2 hospitals in Germany between 1986 and 2007 were studied. Follow-up periods ranged from 6 months to 10 years. Lower urinary tract symptoms were documented in patients with acute brainstem compression because of local chordoma growth. RESULTS: Of 74 patients treated, 22 (7 women, 15 men) with a median age of 37 years were evaluated with voiding diaries and computer urodynamic investigation. Urodynamic testing of 22 symptomatic patients revealed detrusor overactivity in 55%, low compliance bladder in 14%, detrusor-sphincter dyssynergia in 45%, and uninhibited sphincter relaxation in 27%. Despite the description of incomplete emptying and urgency, 4 patients had normal urodynamic findings (18%). Brain magnetic resonance images of the lesions of the symptomatic patients were obtained to determine the side of lesions. CONCLUSION: The dorsolateral pons, including pontine reticular nucleus and the reticular formation and the locus coeruleus, seems to be mainly responsible for lower urinary tract symptoms in our patients with skull base chordoma and brainstem compression.

Expression of vascular endothelial growth factor receptor 2 (VEGFR-2), inducible nitric oxide synthase (iNOS), and Ki-M1P in skull base chordoma: a series of 145 tumors.

Chordomas are locally invasive tumors that have a tendency to relapse despite optimal treatment. Specific biological markers might be used to describe their behavior. There is currently no agreement regarding the best way to manage intracranial chordomas. We studied the expression of vascular endothelial growth factor receptor 2 (VEGFR-2), inducible nitric oxide synthase (iNOS), and Ki-M1P in 145 paraffin-embedded tumors. The purpose of our study was to determine: (a) the role of potent angiogenic factors VEGFR-2 and iNOS and their relationship to each other in skull base chordoma and (b) the role of monocytes/macrophages as a potential iNOS source in the angiogenic process. A series of 74 chordoma patients for a total of 145 lesions (including 71 recurrent lesions) and 10 specimens from embryonic notochord were investigated for the expression of iNOS, VEGFR-2, Ki-M1P, and CD-34 using immunohistochemistry. In the majority of the chordomas, correlations were found between iNOS and the immunoreactivity of Ki-M1P (r = 0.5303, P < 0.0001). Furthermore, the expressions of Ki-M1P was correlated with VEGFR-2 (r = 0.4181, P < 0.0001). Our results indicate that chordomas may respond to receptor tyrosine kinase inhibitors such as VEGFR-2 or modulators of other downstream signaling molecules. The future of VEGFR-2 and iNOS inhibitors as therapeutic agents in the treatment of chordoma will be clearer over the next years as results of the current clinical trials become available and as the factors regulating angiogenesis and the interactions between these factors are elucidated. However, appropriate functional experiments remain to be conducted to prove such a hypothesis.