acute lymphoblastic leukemia ( all ) is the most frequently diagnosed malignancy in children , representing nearly one third of all pediatric cancers . however , being a lymphoid neoplasm , variations exist in the prevalence of subtypes of all , in relation to geographic , environmental , socio - economic , ethnic and racial factors . although various clinical and laboratory prognostic factors like age , sex , hemoglobin level , white blood count ( wbc ) count and response to initial treatment etc . , are used to predict whether a patient will remain in remission or not , immunophenotyping involving different cell surface markers may be considered as an important prognostic factor and also predictor of the outcome . variations of all and its subtypes , especially among children and adolescents in eastern india , have not been well documented till date . thus , the objective of the present study is to examine and correlate variety of cell surface markers in leukemia patients of children and adolescents with respect to disease surveillance and outcome . all patients presenting to netaji subhas chandra bose cancer research institute ( ncri ) , a cancer institute of tertiary care , between march 31 , 2004 and july 31 , 2011 were included in the present study . peripheral blood and/or bone marrow samples were obtained from 500 all patients , within the age range of 2 - 18 years ( median age 10 years ) , prior to treatment . the study group comprised of individuals from both sexes ( male and female ratio 3:2 ) including 321 pediatric ( 2 - 12 years ) and 179 adolescents ( 13 - 18 years ) . no individuals below 2 years and/or above 18 years patients eligibility for participating voluntarily in this study was decided on the basis of preliminary health screening which included collection of individual 's medical history , physical examination and primary diagnosis . immunophenotyping of peripheral blood and/or bone marrow samples was performed by a four color flow cytometer ( facs caliber , becton dickinson , san jose , ca ) . each case was evaluated with a panel of monoclonal antibodies ( cd2 , cd5 , cd7 , cd10 , cd19 , cd22 , cd34 and cd45 ) and cases were assigned immunologic subtypes according to the classification of world health organization ( who ) . routine hematological parameters like hemoglobin , wbc and platelet counts were done using a sysmex semi - automatic analyzer . the overall survival ( os ) , event free survival ( efs ) and disease free survival ( dfs ) rates were calculated . all patients presenting to netaji subhas chandra bose cancer research institute ( ncri ) , a cancer institute of tertiary care , between march 31 , 2004 and july 31 , 2011 were included in the present study . peripheral blood and/or bone marrow samples were obtained from 500 all patients , within the age range of 2 - 18 years ( median age 10 years ) , prior to treatment . the study group comprised of individuals from both sexes ( male and female ratio 3:2 ) including 321 pediatric ( 2 - 12 years ) and 179 adolescents ( 13 - 18 years ) . no individuals below 2 years and/or above 18 years patients eligibility for participating voluntarily in this study was decided on the basis of preliminary health screening which included collection of individual 's medical history , physical examination and primary diagnosis . immunophenotyping of peripheral blood and/or bone marrow samples was performed by a four color flow cytometer ( facs caliber , becton dickinson , san jose , ca ) . each case was evaluated with a panel of monoclonal antibodies ( cd2 , cd5 , cd7 , cd10 , cd19 , cd22 , cd34 and cd45 ) and cases were assigned immunologic subtypes according to the classification of world health organization ( who ) . routine hematological parameters like hemoglobin , wbc and platelet counts were done using a sysmex semi - automatic analyzer . the overall survival ( os ) , event free survival ( efs ) and disease free survival ( dfs ) rates were calculated . in the present population - based investigation , a sample population consisting of 500 consecutive all patients were selected , diagnosed and treated according to national cancer institute protocol ( mcp 841 ) for a prolonged period of 24 - 88 months ( with an average of 54 months ) at ncri , a tertiary care cancer institute in eastern india . majority of cases ( 50.4% ; 252 ) in our sample population was characterized by a higher incidence of t - cell immunophenotype whereas , 47.6% ( 238 ) patients had pro - b , b - cell precursor all and the rest ( 2% ; 10 ) were suffering from mature b - all . predominance of t - all among adolescents was found having distinctive clinical and molecular features , about 60.2% , approximately twice that of pro - b or b - cell precursor all . dfs ( 72.4% ) and efs ( 70.2% ) were significantly better for b - all patients when all 500 patients were considered . for adolescents also , both dfs and efs were higher in case of b - all than t - all [ tables 1 and 2 ] . patients with t - cell subtyping had a significantly lower os ratio [ table 3 ] . moreover , comparatively older patients ( 13 - 18 years ) had relatively inferior outcome ( 61.33% ) in contrast to total patients ( 73.5% ) . 102 cases ( around 20.4% ) studied during diagnosis had an isolated relapse in contrast to 73 cases among older patients , resulting in a significantly higher relapse rate for adolescents [ table 4 ] . toxicity of chemotherapy was also higher in adolescents and t - cell subtypes [ table 5 ] . comparison of dfs between t- and b - lineage all cases of children and adolescents comparison of efs between t- and b - lineage all cases of children and adolescents comparison of efs between t- and b - lineage all cases of children and adolescents comparison of relapse between t- and b - lineage all cases of children and adolescents comparison of toxicity between t- and b - lineage all cases of children and adolescents published reports on incidence and subtypes of all among these patients based on who classification were few from india . in general , prognosis of childhood and adolescent all in the developing world remains poor due to a multitude of adverse clinical and social factors , the most prominent among these being the lack of resources available to both patients and health care professionals . t - lineage all accounted for 44.9% children and 60.2% adolescents . in the west , the predominant immunophenotype observed in all was b - all , accounting for 60 - 80% of total cases , whereas t - all comprised only of 15 - 20% . in india also , studies reported from tata memorial hospital , mumbai , all india institute of medical sciences , new delhi and cancer institute , chennai revealed a declining trend of t - all accompanied by an increasing trend in b - all among children . thus most of these studies have focused predominantly on b - all . moreover , in the existing scenario , specific outcome data for adolescents was relatively sparse . with this in mind , in the present study , we evaluated the immunophenotypic patterns of all in eastern india with special emphasis on patients of 13 - 18 years where all was relatively uncommon but had a worse outcome than younger children . although our overall result demonstrated almost equal prevalence of b- or t - lymphoblastic leukemia , significant heterogeneity was noticed among cases of t - all that correlate with patient age . we noticed a pattern of increased prevalence of t - all among adolescents in this region . our findings recommend that analysis of immunophenotypic subtypes can help to evaluate and predict the outcome of patients with all . thus , this study may help planning for delivery of routine clinical care services and design of new age - focused treatments . we further plan to investigate the effect of socioeconomic and environmental factors in determining the major subtypes of pediatric all cases for a longer period of time . thus , we can select the high risk adolescent and child all by aggressive chemotherapy protocol like berlin - frankfurt - munich to render better outcome .
objective : research in eastern india especially among children and adolescents for acute lymphoblastic leukemia ( all ) have not been well documented until recently when it was conducted at a cancer institute of tertiary care with primary objectives of examining and correlating different cell surface markers involved with respect to disease surveillance thereby highlighting it as a strong prognostic marker for future diagnosis and treatment.materials and methods : a total of 500 consecutively selected all patients were diagnosed and treated according to national cancer institute protocol ( mcp 841 ) for a period of 24 - 88 months during this hospital - based study.results:of the total , 50.4% had a higher incidence of t - all and 47.6% had pro - b , b - cell precursor all . 
 disease free survival and event free survival were remarkably higher in b - all adolescent patients as compared to t - all , who had significantly lower overall survival ratio . 
 prevalence of t - all was also observed in relapse cases for adolescent patients.conclusions:we conclude that there is an increased prevalence of t - all among adolescents in eastern india . 
 immunophenotypic analysis might help in proper evaluation and prediction of treatment outcomes with an increased thrust on studying age - specific incident rates enabling well planned future treatments for improved and better outcome .