OBJECTIVETo investigate and compare the clinical implications of p16 deletion in childhood and adult B-lineage acute lymphoblastic leukemia (B-ALL).

METHODSA total of 129 cases of de novo childhood (73 cases) and adult (56 cases) B-ALL were examined genetically and immunologically using G-banding techniqhe, interphase fluorescence in situ hybridization (I-FISH) and immunophenotyping by flow cytometry, and their clinical data were retrospectively analyzed.

RESULTSOf 73 childhood cases, the prevalences of homozygous deletion, hemizygous deletion and no deletion of p16 were 24.7% (18 cases), 6.8% (5 cases) and 68.5% (50 cases) respectively, and of 56 adult cases, the incidences as of 14.3% (8 cases), 8.9% (5 cases) and 76.8% (43 cases) respectively. The incidence of p16 deletion between the two groups had no significant difference (P = 0.338). In both groups, patients with or without p16 deletion had no significant difference in terms of white blood cells (WBC) count at diagnosis, BM blast percentage, chromosome karyotype, extra-infiltration and CR1 rate. Of note, there were 2 cases, each in childhood and adult, showed no deletion at the time of diagnosis, their p16 deletions occurred at relapse. The deletion of p16 was associated with poor overall survival and event-free survival (EFS) in both childhood and adults. According to the standard of NCI risk stratification, we divided patients of two groups into standard and high risk category respectively, and performed further analysis. The significance of different risk category in children and adults was disparity. The overall survival (OS) rates of deletion and no deletion of p16 were 45.3% and 79.8% (P = 0.006) in children, and 7.7% and 22.6% (P = 0.002) in adults, respectively. EFS rates of deletion and no deletion of p16 were 33.5% and 58.1% (P = 0.008) in children, and 0 and 10.9% (P < 0.01) in adults, respectively. Of the standard risk category in children, OS rates of deletion and no deletion of p16 were 46.8% and 89.3% (P = 0.015) respectively, and EFS rates of deletion and no deletion of p16 as of 40.9% and 82.1% (P = 0.007) respectively. Of the high risk category in children, OS rates of deletion and no deletion of p16 were 41.7% and 67.4% (P = 0.193) respectively, and EFS rates of deletion and no deletion of p16 were 25.0% and 25.6% (P = 0.305) respectively. Of the standard risk category in adults, OS rates of deletion and no deletion of p16 were 20.0% and 46.9% (P = 0.092) respectively, and EFS rates of deletion and no deletion of p16 were 0 and 25.0% (P = 0.062) respectively. Of the high risk category in adults, OS rates of deletion and no deletion of p16 were 0 and 12.4% (P < 0.001) respectively, and EFS rate of deletion and no deletion of p16 was 0 and 4.8%(P < 0.001), respectively.

CONCLUSIONThis study indicated that deletion of p16 was associated with poor prognosis in both childhood and adult B-ALL, which highlighted an important significance to define the status of p16 in both childhood and adult B-ALL for predicting prognosis and guiding clinical intervention.

Adult ; Child ; Female ; Gene Deletion ; Genes, p16 ; Humans ; Male ; Precursor B-Cell Lymphoblastic Leukemia-Lymphoma ; genetics ; Prognosis ; Retrospective Studies

BACKGROUND: Cerebrospinal fluid (CSF) has been demonstrated as a better source of circulating tumor DNA (ctDNA) than plasma for brain tumors. However, it is unclear whether whole exome sequencing (WES) is qualified for detection of ctDNA in CSF. The aim of this study was to determine if assessment of ctDNA in CSF by WES is a feasible approach to detect genomic alterations of glioblastoma. METHODS: CSFs of ten glioblastoma patients were collected pre-operatively at the Department of Neurosurgery, Sun Yat-sen University Cancer Center. ctDNA in CSF and genome DNA in the resected tumor were extracted and subjected to WES. The identified glioblastoma-associated mutations from ctDNA in CSF and genome DNA in the resected tumor were compared. RESULTS: Due to the ctDNA in CSF was unqualified for exome sequencing for one patient, nine patients were included into the final analysis. More glioblastoma-associated mutations tended to be detected in CSF compared with the corresponding tumor tissue samples (3.56 ± 0.75 vs. 2.22 ± 0.32, P = 0.097), while the statistical significance was limited by the small sample size. The average mutation frequencies were similar in CSF and tumor tissue samples (74.1% ± 6.0% vs. 73.8% ± 6.0%, P = 0.924). The R132H mutation of isocitrate dehydrogenase 1 and the G34V mutation of H3 histone, family 3A (H3F3A) which had been reported in the pathological diagnoses were also detected from ctDNA in CSF by WES. Patients who received temozolomide chemotherapy previously or those whose tumor involved subventricular zone tended to harbor more mutations in their CSF. CONCLUSION Assessment of ctDNA in CSF by WES is a feasible approach to detect genomic alterations of glioblastoma, which may provide useful information for the decision of treatment strategy.