PlGF and VEGF-A Regulate Growth of High-Risk MYCN-Single Copy Neuroblastoma Xenografts via Different Mechanisms.

Neuroblastoma (NB) is the most common extracranial solid tumor of childhood and is a rapidly growing, highly-vascularized cancer. NBs frequently express angiogenic factors and high tumor angiogenesis has been associated with poor outcomes. Placental growth factor (PlGF) is an angiogenic protein belonging to the vascular endothelial growth factor (VEGF) family and is up-regulated mainly in pathologic conditions. Recently, PlGF was identified as a member of a gene expression signature characterizing highly malignant NB stem cells drawing attention as a potential therapeutic target in NB. In the present study, we sought to investigate the expression of PlGF in NB patients and the effect of PlGF inhibition on high-risk MYCN-non-amplified SK-N-AS NB xenografts. Human SK-N-AS cells, which are poorly differentiated and express PlGF and VEGF-A, were implanted subcutaneously in athymic nude mice. Treatment was done by intratumoral injection of replication-incompetent adenoviruses (Ad) expressing PlGF- or VEGF-specific short hairpin (sh)RNA, or soluble (s)VEGF receptor 2 (VEGFR2). The effect on tumor growth and angiogenesis was analyzed. High PlGF expression levels were observed in human advanced-stage NBs. Down-regulating PlGF significantly reduced NB growth in established NB xenografts by reducing cancer cell proliferation but did not suppress angiogenesis. In contrast, blocking VEGF by administration of Ad(sh)VEGF and Ad(s)VEGFR2 reduced tumor growth associated with decreased tumor vasculature. These findings suggest that PlGF and VEGF-A modulate MYCN-non-amplified NB tumors by different mechanisms and support a role for PlGF in NB biology.

Endosonographic assessment of rectal cancer after neoadjuvant radiotherapy.

AIM: To assess the changes in the angiogenic status of rectal cancer before and after preoperative radiotherapy (RT) using endosonography (ES). MATERIAL AND METHODS: Fifty-four patients with rectal cancer were examined by ES before and 6-7 weeks after preoperative RT and . The tumour size, stage, echostructure and vascularization before and after RT were compared. Tumour vascularization was determined by qualitative power Doppler and by computer-assisted method. RESULTS: Compared to the histological data, ES restaging after RT was accurate in 65% of the cases for the T parameter and in 83% for the N parameter (TNM tumour classification). The histological data compared with the initial ES examination revealed downstaging in relation to the T parameter in 33% and for the N stage in 24% of the cases. The tumour structure following RT became hyperechogenic in 89% of tumours and remained hypoechogenic in 11% of tumours. Power Doppler found a reduction in tumour vascularization after RT in 61% of the tumours. The PDVI before RT was 10.7+/-5.8% and 6.3+/-4.6% after RT (р<0.05). A strong correlation between the qualitative assessment of the vascularization and PDVI was found (r=0.536, p<0.001). The vascularization reduction after RT was found to be a protective factor which decreased the death risk by about 86 % (ОR=0.14, р=0.001). CONCLUSIONS: Endorectal Doppler sonographic findings are promising in the evaluation of tumour vascularization in patients with rectal cancer. The qualitative and quantitative digital assessment of the vascularization gives supplementary information about the patients' prognosis.

Topical anal fissure treatment: placebo-controlled study of mononitrate and trinitrate therapies.

AIM: The present study aims to evaluate and compare the efficacy of two nitrate gels, containing isosorbide-5-mononitrate (ISMN) or glyceryl trinitrate (GTN), in the therapy of chronic anal fissure. MATERIALS AND METHODS: The patients were randomly assigned to three groups: 0.1% ISMN gel (21 patients), 0.1% GTN gel (21 patients) and a placebo group (ten patients). The ethic committee of our hospital approved the protocol and informed consent was obtained from all participants. All patients underwent clinical examination, visual inspection of the fissure and anal manometry prior to and after therapy. RESULTS: The chronic anal fissure was completely healed in 71% of the patients treated with ISMN, 67% with GTN and in 30% from the placebo group. One patient in the ISMN group reported mild headache. Three patients in the GTN group had anal burning. CONCLUSION: Both topical nitrate treatments (ISMN and GTN) were effective for chronic anal fissures. The reduction of the anal pressure was slightly higher after ISMN treatment (28%) than the treatment with GTN (23%). However, the statistical difference was not significant (p>0.05).

Endosonographic assessment of the response of rectal cancer to preoperative radiotherapy endosonographic assessment of the response of rectal cancer to preoperative radiotherapy.

BACKGROUND/AIMS: The accuracy of endoluminal ultrasonographic restaging of rectal cancer after chemoradiation has not been extensively studied and its definitive clinical utility has yet to be defined. The aim of the present study is to assess the benefit of endoluminal ultrasonography with Doppler evaluation for rectal cancer restaging after preoperative radiotherapy. METHODOLOGY: Twenty six patients (10 female, 16 males, mean age--58 years) with histologically proven rectal cancer underwent preoperative radiotherapy. All patients were examined by endoluminal (endorectal or endovaginal) ultrasonography. Endosonography was repeated on 13 patients after small fractions preoperative radiotherapy. RESULTS: The mean transversal diameter of lesions before preoperative radiotherapy established by endoluminal ultrasonography is 33mm +/- 11 mm. After preoperative radiotherapy we detect significant reduction of 33% in the transversal tumor size--mean 23mm +/- 7mm (p < 0.001). After radiation the mean distance from the tumor to the internal anal sphincter increases without statistical significance by 5%: from 59 +/- 18 mm to 62 +/- 16 mm (p = 0.165). Compared to histological data, endosonographic restaging after radiotherapy is accurate in 9/13 (69%) for T parameter and 11/13 (85%) for N. After preoperative radiotherapy tumor sonographic structure is hyperechoic (homogeneous or inhomogeneous)--in 9 patients and only in 4 cases the tumor remains hypoechoic. Power Doppler exam before radiotherapy shows poor vascularization in 5 tumors--(19%). Abundant vascularization is found in 9 cases--(35%). In the remaining 12 patients tumor vascularization is considered as moderate. In 8 out of 13 cases (61.5%) after radiotherapy, vascular signals are less expressed. Lack of vascular alterations on pulse color and power Doppler flow is detected in the remaining 5 patients. No patients have more expressed vascularization on power Doppler examination after radiotherapy. CONCLUSION: According to our results the accuracy of endosonographic restaging after radiotherapy is lower for assessment of T criterion and is better for N parameter. Doppler findings are promising in the evaluation of tumor vascularity, respectively its predictive and prognostic values.

Contrast-enhanced endoanal and transperineal sonography in perianal fistulas.

BACKGROUND/AIMS: To improve the diagnostic potential of ultrasound in patients with perianal fistulas, by performing a combined perineal and endorectal Doppler sonography investigation before and after contrast enhancement with hydrogen peroxide. METHODOLOGY: Ten patients (9 male and 1 female) with perianal fistulas were tested. After contrast-free transperineal and endoanal sonography, hydrogen peroxide was injected in the fistulas and the ultrasound examinations were repeated. RESULTS: All fistulas were identified by conventional endoanal and transperineal sonography. The contrast application gave more detailed information about the location of the fistula in relation to the anal lumen and sphincters. The fistulas were distributed as follows: intersphincteric - in 5 patients, transsphincteric - in 2 and extrasphincteric complicated (with 1 or more secondary tracks) fistula - in 3 patients. The findings have been confirmed intraoperatively in 9 patients that underwent an operation. Hypervascularization of the wall was detected in 4 patients by means of Doppler investigation which also differentiated arterial blood flow in 3 cases and venous blood flow in one. CONCLUSIONS: The application of the contrast-enhanced endoanal and transperineal sonography offers a more detailed perianal fistula imaging. In addition the Doppler technique can further characterize their blood supply.