Vascular endothelial growth factor [VEGF-C] signaling through KDR [VEGFR-2] and FLT-4 [VEGFR-3] mediates leukemic cell proliferation and survival

VEGF, a key angiogenic molecule, is a multifunctional cytokine that acts both as a potent inducer of vascular permeability and as a specific endothelial cell mitogen. Because of its effects on endothelial cell growth and microvascular permeability, VEGF is believed to be an important mediator of tumor angiogenesis. Leukemic cells not only release VEGF but also express its receptors, resulting in the establishment of an autocrine loop that supports their migration and survival. VEGF-C may play an important role in the pathophysiology of hematopoietic malignancies by not only regulation of lymphangiogenesis, in vivo, but also by promotion of angiogenesis invasion of neoplastic cells into lymphatic vessels and enhancing lymphatic metastasis during tumor progression. although it is well established that growth in solid tumors is dependent on the formation of neovasculature, the role of angiogenesis in hematopoietic neoplasms has not been determined. The present study was undertaken to identify whether VEGF-C and its receptors VEGFR-2 [KDR] and VEGFR-3 [FLT-4] were expressed in patients with denovo acute leukemia by RT-PCR and to evaluate the relationship between their expression and clinical, laboratory findings and prognosis. Using reverse transcription polymerase chain reaction analysis [RT-PCR], 30 de novo acute leukemia patients [20 ALL patients and 10 AML patients] as well as 10 controls were tested for the expressions of VEGF-C, VEGFR-3 [FLT 4] and VEGFR-2 [KDR] genes. In the current study, VEGF-C, FLT-4 and KDR were detected in 10% of control samples. In ALL patients VEGF C was expressed in 65% of cases, FLT-4 in 70% of cases and KDR in 30% of cases. The expressions of VEGF-C, FLT-4 and KDR in ALL patients were associated with increased risk of leukemia [with OR 16.7 and 95% CI 1.7-160.4, OR 21.0 and 95% CI 2.2-204.6 and with OR 3.9 and 95% CI 0.4-37.6 respectively]. In AML patients, VEGF-C was expressed in 60% of cases, FLT-4 in 70% of cases and KDR in 40% of cases. The expression of VEGF-C, FLT-4 and KDR in AML patients was associated with increased risk of leukemia [with OR 13.5 and 95% CI 1.2-152.2, OR 21.0 and 95% CI 1.8-248.1 and OR 6.0 and 95% CI 0.5-67.7 respectively]. In the 6 followed-up ALL patients, 3 [50%] were in remission, three of them were VEGF-C negative, 2 were FLT4 positive and 1 was KDR positive. 2 of the 6 ALL patients [33.3%] were resistant to treatment, both were VEGF-C positive, FLT-4 positive and 1 was KDR positive. One of the 6 ALL patients [16.6% died during induction, this patient was VEGF-C positive and FLT-4 and KDR negative. In the 4 followed-up AML patients, 3 of them [75%] were in remission, 1 of the 3 was VEGF-C positive and 2 were FLT-4 positive. One of the four AML patients [25%] was resistant to treatment, this patient was VEGF-C, FLT-4 and KDR positive. The number of VEGF-C positive patients with no treatment failure was lower than the number of VEGF-C positive patients with treatment failure. Also, the risk of failed induction was found to be greater in VEGF-C positive patients than in VEGF-C negative patients, thus, the expression of VEGF-C and its receptors [FLT-4 and KDR] in ALL and AML patients was associated with increased risk of leukemia and unfavorable treatment outcome. VEGF-C and its receptors KDR [VEGFR-2] and FLT-4 [VEGFR-3] may play an important role in the pathophysiology of hematopoietic malignancies and may actually contribute to the development of leukemia. Also, owing to the importance of angiogenesis in tumor progression and the effects of VEGF-C, KDR and FLT-4 in chemotherapy-treated leukemias, inhibition of VEGF-C signaling represents an attractive cancer treatment

Behavior disorders among primary school children associated with some visual problems and socio-demographic factors

The study was conducted on 206 primary school children aged from 7to12 years; males were equal to females, N=103 for each sex. It was carried out in both an urban area in Tanta City and part of Kuhafa region as a rural community. It aimed at studying behavior disorders among primary school children and their association with some visual errors and socio-demographic data. All cases in this study had visual errors and were classified into two groups,the first group had only simple refractive errors [from 1/4 to 1/2 diopters] and they were one hundred and ninety six cases while the second group had severe visual disorders and they were only ten cases. Two sheets were used one for the socio-demographic factors and the other for the children behavior questionnaire [CBQ] developed by Rutter [teachers scale]. Out of the total studied sample, 25[12.1%] had behavior disorders. Age groups, sex and birth order were not significantly affecting behavior disorders, yet it was recorded that behavior problems decreased as getting older. Advanced eye problems namely, strabismus [squint], amblyopia and high myopia [10 cases] were significantly associated with behavior disorders. Behavior disorders among the majority of cases with simple refractive errors were significantly recorded among children with low parental education [21.3% were maladjusted children of low paternal education compared to 3.4% with high education and 18.4% were maladjusted children with low maternal education compared to 3.7% with high education, [p<0.05], with non-working mothers [14.2%] were maladjusted children with non working mothers compared to 2.9% with working mothers, [p<0.05], with nuclear family structure and with rural residence [16 were maladjusted rural children and four urban]. Low scholastic achievement was significantly associated with high frequency of behavior disorders among the majority of cases. Advanced visual disorders [10 cases] were the most significant predictor for maladjustment among the studied sample by logistic regression analysis