Expression And Significance Of PHOX2B And ALK In Children Neuroblastoma

Objective: Neuroblastoma(NB)is the most common extra-cranial solid tumor in patients who are under 15 years old, and the most frequently diagnosed type of cancer during the first year of life.The incidence of NB is about 1 case per 7000 babies born per year,and the median age at diagnosis is 18 months.NB leads to approximately 10% of cancer-related deaths.It is generally considered that neuroblastoma originates from neural crest cells in the paravertebral sympathetic ganglia and the adrenal medulla.However, the mechanism of how neuroblastoma arises during sympathetic neurogenesis and the cellular mechanism that drives neuroblastoma development remains unclear. Many patients cannot be aware of this disease until it is too late.In cases of metastases, these are most commonly observed in bone marrow, bone, lymph nodes, liver or subcutaneous tissue.The hallmark of NB is its wide range of clinical courses,with,on the one hand,a possibility of cellular maturation or spontaneous regression even in case of metastatic disease,or on the other hand, life-threatening tumor progression despite all treatment. So prognostic factors have necessity to identify high risk groups and to stratify treatment approaches.Recently,except age,stage and pathological features,some scholars find that NSE>100?g/L,SF>150ng/L and LDH>800U/L can help distinguish progressive neuroblastomas from favorable ones.Despite intensive multimodal treatment,the 5-year event-free survival of patients with high-risk neuroblastoma is less than 40%. Both paired-like homebox 2B(PHOX2B) and anaplastic lymphoma kinase(ALK) are involved into the occurrence and development of family NB.But how they work in sporadic NB is unknown.Therefore,we try to study the expression of PHOX2B and ALK in NB tissues,and the relationship between these two factors and gender,age,stage,pathological features,the level of NSE,SF and LDH.We also try to explore the correlation between the two factors.In this way,we hope to find out the roles of these two factors play in NB development,and the new target treatment for metastatic patients.Method: We detected the expression of PHOX2B and ALK in 40 cases of NB by immunohistochemical(IHC) staining.These cases came from The Pediatrics of The Fourth Hospital of Hebei Medical University,which were confirmed by pathological diagnosis from January 2005 to October 2015.ALL the cases were classified into different groups according to gender,age,stage,pathological type and clinical features.Another 15 cases of normal lymph nodes which were received from surgical resection,were used as control group.The data were analyzed with SPSS 13.0 software to explore the expression and correlation of these two factors.Result: 1 The expression of PHOX2B in NB tissues 1.1 Comparison between groups 87.5% cases of NB tissues studied showed positive PHOX2B staining in the neuropils of NB cells while no case of control group showed positive staining.The difference had statistical significance(P<0.01).And 77.5% cases of NB tissues showed high PHOX2B expression. 1.2 Comparison within group It was expressed in 72.73% cases of ?-? stage NB and 93.10% cases of ?stage NB,the difference had no statistical significance(P=0.228).High PHOX2B expression is showed in 36.36%?-? stage cases and 93.10% ? stage cases,the difference had statistical significance(P=0.001). It was expressed in 96.77% cases of NB,83.33% cases of ganglioneuroblastoma(GNB)and no case of ganglioneuroma(GN),the difference had statistical significance(P < 0.01).There was a significant difference in the positive rate of NB and GN(P=0.001),but on difference in the positive rate of NB and GNB,GNB and GN(P>0.017).High expression of PHOX2B is showed in 87.10% NB cases,66.67% GNB cases and 0% GN cases,the difference had statistical significance(P=0.002).There was a significant difference of NB and GN in the high expression of PHOX2B(P=0.006),but no difference of NB and GNB,GNB and GN in the high expression of PHOX2B(P>0.017). The expression of PHOX2B had no correlation with gender,age and the level of NSE,SF,LDH. 2 The expression of ALK in NB tissues 2.1 Comparison between groups 82.5% cases of NB tissues studied showed positive ALK staining in the cytoplasm of NB cells while no case of control group showed positive staining.The difference had statistical significance(P<0.01).And 62.5% cases of NB tissues showed high ALK expression. 2.2 Comparison within group It was expressed in 73.91% male cases and 94.12% female cases,the difference had no statistical significance(P=0.214).High ALK expression is showed in 47.83% male cases and 82.35% female cases,the difference had statistical significance(P=0.026). It was expressed in 50% cases who was under 18 months and 93.33% cases who was over 18 months,the difference had statistical significance(P=0.008).High ALK expression is showed in 40% cases who was under 18 months and 70% cases who was over 18 months,the difference had statistical significance(P=0.187). It was expressed in 54.55% cases of?-? stage NB and 93.10% cases of ?stage NB,the difference had statistical significance(P=0.016).High ALK expression is showed in 36.36%?-? stage cases and 72.41% ? stage cases,the difference had statistical significance(P=0.035). The expression of ALK had no correlation with pathological type and the level of NSE,SF,LDH. 3 Spearman rank correlation analysis The expression of PHOX2B and ALK in children NB tissues was positively correlated(r=0.600,P<0.001).Conclusion: 1 The positive expression rate of PHOX2B in NB is much higher than in GNB and GN,so PHOX2B can be used as an indicator to judge the degree of tumor cell differentiation. 2 The expression of ALK is related to age.As the age increased,the positive expression rate of ALK increased. 3 The positive expression rate of ALK had correlation with disease stage,so we speculate that ALK can help us to distinguish the malignant degree of tumor and find out the new target for treatment of patients in advanced stage. 4 The expression of PHOX2B and ALK were significantly higher in the children NB tissues,and the correlations between PHOX2B and ALK were positively correlated,namely the higher the expression of PHOX2B,the higher the expression of ALK protein,which suggested that PHOX2B regulates the expression of ALK protein in vivo as a transcription factor.