Application of Next Generation Sequencing in Genetic Diagnosis of Hereditary Platelet Disorders - Review / 中国实验血液学杂志

Hereditary platelet disorders are a heterogeneous group of disorders characterized by abnormal number or function of platelets, sometimes even involving other systems apart from blood abnormalities. The great clinical and genetic heterogeneity makes the diagnosis and treatment of hereditary platelet disorders as a huge challenge for clinicians. At present, only a small number of patients have received a clear molecular diagnosis of hereditary platelet diseases, and a lot of pathogenic genetic variations still remain unknown. The popularity of next generation sequencing (NGS) promotes the development of individualized gene sequencing. Researchers have made great progress in the field of hemostasis and thrombosis using whole genome sequencing (WGS), whole exone sequencing (WES) and target gene sequencing (TGS). The development of NGS has not only promoted the individualized molecular diagnosis of hereditary platelet diseases, but also laid a solid foundation for gene therapy in the future. In this review, the new progress of the diagnosis of platelet-related diseases by using next generation sequencing techniques, is summarized.

Clinical characterization and mutation identification for multiple sulfatase deficiency patients in China / 中华儿科杂志

<p><b>OBJECTIVE</b>Multiple sulfatase deficiency is a rare autosomal recessively inherited lysosomal storage disorder characterized by the accumulation of sulfated lipids and acid mucopolysaccharides. The aim of this study was to explore the clinical manifestations, enzyme activities and SUMF1 gene mutations in two Chinese patients with multiple sulfatase deficiency.</p><p><b>METHOD</b>One boy and one girl from two families were studied. Both patients presented with mental retardation, mild coarse facial features, a neurodegenerative course of disease with loss of sensory and motor function after 2 years of age, ichthyosis and skeletal abnormalities (kyphosis or/and scoliosis). Clinical characteristics indicate multiple sulfatase deficiency.Sulfatases activities in blood leucocytes, plasma or cultured fibroblast of the patients were measured.Genomic DNAs were extracted from peripheral blood leukocytes from the patients and their parents. All SUMF1 gene exons and intron-exon boundaries were amplified by PCR and subjected for direct sequencing.</p><p><b>RESULT</b>In case 1, five sulfatases activities of blood leucocytes and four sulfatases of cultured skin-fibroblasts were analyzed.In case 2, three sulfatases activities of blood leucocytes were tested.Significantly decreased sulfatases activities confirmed the diagnosis of multiple sulfatase deficiency.On SUMF1 gene, c.793_794 insATG (p. P265X)/ c.1045C>T (p.R349W) in case 1 and c.451A>G (p.K151E)/ c.1046G>C (p.R349Q) in case 2 were detected, respectively. Three novel mutations c.793_794insAGT, c.1046G>C and c.451A>G were identified.</p><p><b>CONCLUSIONS</b>Multiple sulfatase deficiency usually results in multi-organ damage, especially neurologic, skeletal and skin.Sulfatases assay and SUMF1 gene analysis are necessary for the diagnosis. Two Chinese cases with multiple sulfatase deficiency were firstly reported. Three novel mutations were found.It should be considered that the mutation profile of SUMF1 gene in Chinese patients is different from other populations.</p>

Mutation analysis of 11 Chinese patients with attenuated mucopolysaccharidosis type / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>Mucopolysaccharidosis type I (MPS I) is an autosomal recessive disease resulting from the deficiency in the lysosomal enzyme alpha-L-iduronidase (IDUA). The present study was conducted to identify IDUA gene mutations in attenuated (MPS I H/S and MPS I S) patients with MPS I in northern China.</p><p><b>METHODS</b>Fourteen exons with adjacent intronic sequences of the IDUA gene in 11 MPS I patients were amplified by polymerase chain reaction (PCR), and the PCR products were sequenced directly and origin analysis was conducted.</p><p><b>RESULTS</b>Seven mutations were detected in the 11 MPS I patients, i.e., c.236 C to T (p. A79V), c.266 G to A (p.R89Q), c.265 C to T (p.R89W), c.532G to A (p.E178K), c.589G to A (p.G197S), c.1037T to G (p.L346R), and c.1877 G to A (p.W626X). All of them were known mutations. Six patients were homozygotes and 1 was heterozygote with nonsense mutation. In addition, 9 reported single nucleotide polymorphism (SNP) were detected, i.e., p.A8, p.A20, p.H33Q, p.R105Q, p.A314, p. A361T, p.T388, p.T410 and p.V454I.</p><p><b>CONCLUSION</b>The mutation spectrum of the IDUA gene in attenuated MPS I Chinese patients may be different from that in patients from other countries.</p>

Two novel EIF2AK3 mutations in a Chinese boy with Wolcott-Rallison syndrome / 中华儿科杂志

<p><b>OBJECTIVE</b>Wolcott-Rallison syndrome (WRS) is a rare autosomal recessive disorder characterized by the association of permanent neonatal or early-infancy insulin-dependent diabetes, multiple epiphyseal dysplasia and growth retardation, and other variable multisystem clinical manifestations. Here we describe a Chinese boy affected by WRS. Genetic testing of his EIF2AK3 gene was performed in order to elucidate molecular variations and subsequently to provide credible genetic counseling for prenatal diagnosis in his family.</p><p><b>METHOD</b>Based on analysis of a nine-year-old boy's clinical symptoms associated with biochemical examination and imaging, the diagnosis of WRS was therefore made. Genomic DNAs were extracted from peripheral blood leukocytes from the boy and his parents with their informed consent for genetic studies. All EIF2AK3 exons and intron-exon boundaries were amplified by Touch-down polymerase chain reaction (Touch-down PCR) and sequenced.</p><p><b>RESULT</b>Direct sequencing of PCR products revealed the presence of a heterozygous T insertion (c.1408_1409insT) in exon 8 of the EIF2AK3 gene leading to frameshifting and termination, and another heterozygous T to A exchange (c.1596T > A) in exon 9 of the EIF2AK3 gene resulting in nonsense C532X mutation.</p><p><b>CONCLUSION</b>Combining mutation screening of EIF2AK3 gene with clinical manifestations and effective examination may provide a reliable diagnostic method for patients. In this research, two novel mutations identified in the Chinese boy locate in the catalytic domain of the EIF2AK3 gene, disrupting the ability of autophosphorylation, leading to the truncated proteins that are unable to phosphorylate the natural substrate, which are responsible for the phenotype of Wolcott-Rallison syndrome.</p>

Mutation analysis and prenatal diagnosis of 2 cases with mucopolysaccharidosis type I / 中华儿科杂志

<p><b>OBJECTIVE</b>Mucopolysaccharidosis type I (MPS I; MIM# 252800) is an autosomal recessive disease that results from the deficiency in the lysosomal enzyme α-L-iduronidase(IDUA). IDUA is one of the enzymes involved in degradation of glycosaminoglycans heparan sulphate and dermatan sulphate. The deficiency of IDUA leads to widespread accumulation of partially degraded mucopolysaccharides inside lysosomes, resulting in progressive cellular and multiorgan dysfunction. Up to now there is no definitely effective treatment for this disorder, therefore it is important to provide an accurate genetic diagnosis and prenatal diagnosis for the MPSI families. This study was conducted to detect IDUA gene mutation in patients with MPSIand make a definite diagnosis of homozygote or heterozygote and make first trimester prenatal diagnosis.</p><p><b>METHOD</b>The 2 male probands included in this study were diagnosed as MPSI patients in Peking Union Medical College Hospital, case 1 was 2 years old and case 2 was 5 years old. Genomic DNA was extracted from leucocytes in the 2 patients and 2 mothers' cultured amniocytes. IDUA gene DNA sequence was amplified by polymerase chain reaction (PCR) and the PCR products were sequenced directly. Novel mutations were analyzed in 100 normal chromosomes.</p><p><b>RESULT</b>The genotype of case 1 was p.L238R/c.883InsC, while of case 2 was c.531InsT/p.L346R. The fetal case 1 did not inherit the same pathogenic mutations as proband 1, the activity of the IDUA in amniocytes was 9.0 nmol/(h·mg pr). The fetal case 2 inherited the same pathogenic mutations with the proband, the genotype of fetal 2 was c.531InsT/p.L346R, the activity of the IDUA in amniocytes was 0.5 nmol/(h·mg pr).</p><p><b>CONCLUSION</b>Of the 4 mutations found in 2 MPS I patients, p. L238R, c.883InsC, c.531InsT were novel. The fetal case 1 was diagnosed as normal fetus while the fetus 2 was diagnosed as affected. The results of the two kinds of prenatal diagnostic methods were correspondent with each other.</p>

Mutation analysis of PTPN11 gene in Noonan syndrome / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To investigate the mutations in protein tyrosine phosphatase, nonreceptor-type 11 (PTPN11) gene in patients with Noonan syndrome (NS).</p><p><b>METHODS</b>Three sporadic patients with NS were studied. Genomic DNAs were extracted from peripheral blood leukocytes. All 15 coding exons and their flanking intronic boundaries of the PTPN11 gene were amplified by polymerase chain reaction and followed by direct sequencing. DNAs from parents were sequenced in the corresponding region when the mutation was detected in their affected child. The identified mutation was screened in 100 healthy individuals for exclusion of polymorphism by restriction endonuclease digestion of the PCR products. Protein conservation analysis was performed among 10 species using an online ClustalW tool.</p><p><b>RESULTS</b>Direct DNA sequence analysis identified a heterozygous 181G to A change in exon 3 of the PTPN11 gene in one patient, which resulted in the substitution of an aspartic acid residue by an asparagine at codon 61. The mutation was absent in his parents and 100 controls, and is located in a highly conserved amino acid site. No mutation in the coding region of PTPN11 gene was observed in the other two patients.</p><p><b>CONCLUSION</b>The p.D61N mutation was reported previously in Caucasians and is a de-novo mutation in this patient. Our study further confirmed that the p.D61N is a pathogenic mutation for NS and consistent with the clinical diagnosis. Additional genes may be involved in the other two patients with NS, indicating high genetic heterogeneity of this disease.</p>

A Chinese girl with fibrodysplasia ossificans progressiva caused by a de novo mutation R206H in ACVR1 gene / 中华儿科杂志

<p><b>OBJECTIVE</b>Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant inherited disease caused by mutations of ACVR1 gene and can be inherited from either mother or father. FOP is characterized by the presence of malformations of the big toes and of progressive extra-skeletal ossification. Direct sequence analyses of genomic DNA have demonstrated that there is an identical single nucleotide substitution (c617G-->A, R206H) in the glycine-serine (GS) activation domain of ACVR1 gene, responsible for all affected individuals reported so far. We report a Chinese girl with typical FOP characteristics, in whom the same mutation in ACVR1 was identified.</p><p><b>METHODS</b>Clinical diagnosis was based on physical examination, radiological findings, and biochemical tests. For mutation detection, peripheral blood was obtained with informed consent from the patient and the parents. Genomic DNA was extracted from peripheral blood using standard method. Exon 4 of ACVR1 was amplified by polymerase chain reaction (PCR), and the PCR products were subjected to automatic DNA sequencing.</p><p><b>RESULTS</b>The affected girl is 3-year-old and showed typical clinical manifestations of FOP. She had malformations of the halluces at birth and subsequently progressive extra-skeletal ossification developed at the age of 8 - 9 months. Then, she gradually developed stiffness of the knee joint and neck but remained ambulant. Radiographic changes were observable, e.g., the extra-skeletal ossification was found at cervical spine. Her mother has congenital malformations of the halluces, but had no postnatal progressive extra-skeletal ossification. Her father and other family members are normal. With direct sequencing of the PCR products, a G to A substitution at c617 of ACVR1 (R206H) was detected in the patient only but not in her parents. Paternity analysis suggested that it is a de novo mutation.</p><p><b>CONCLUSION</b>This is the first case reported in a Chinese patient with FOP in the mainland of China, which was confirmed by direct sequencing. Although sporadic cases of FOP have been reported in diverse geographic and ethnic group, the mutations of ACVR1 c617 (R206H) are identical up to now. The presence of mutation hot spot facilitates molecular diagnosis in clinical practice. Genetic detection is important for FOP patients to avoid misdiagnosis and further damages, including those from medical intervention.</p>

Postnatal and prenatal diagnosis of mucopolysaccharidosis type III (Sanfilippo syndrome) / 中华儿科杂志

<p><b>OBJECTIVE</b>Mucopolysaccharidosis (MPS) types IIIA, B, C, D are a group of autosomal recessive lysosomal storage disorders caused by mutations in one of four genes which encode enzyme activities required for the lysosomal degradation of heparan sulfate. MPSIIIA and MPSIIIB involve deficiencies of heparan N-sulfatase (SGSH) and alpha-N-acetylglucosaminidase (NAGLU). MPS IIIA and MPS IIIB are more common than MPS IIIC and IIID. The present study aimed to establish two enzyme assay methods for SGSH and NAGLU activities for carrying out postnatal and prenatal diagnosis of MPSIIIA and IIIB by means of SGSH and NAGLU activity assay on plasma, leukocyte, uncultured chorionic villi (CV) and cultured amniotic fluid cells (AF cell) using two newly synthesized substrates. Mutation analysis of SGSH gene was also performed.</p><p><b>METHODS</b>Two fluorigenic substrate (4-methylumbelliferyl-alpha-D-N-sulphoglucosaminide.Na and 4-methylumbelliferyl-alpha-N-acetylglucosaminide) were used for the assay of SGSH and NAGLU activity. SGSH activity in leukocyte was determined for diagnosis MPSIIIA proband. NAGLU activity was determined in plasma for diagnosis of MPSIIIB proband. Twelve cases with MPS III were enrolled in this study, 4 were female and 8 were male, age 3 - 10 years and were from 10 unrelated families. Eight exons of SGSH gene were amplified by PCR. The mutations of the patients were characterized by direct sequencing of the amplified DNA fragments. Prenatal diagnosis in 3 pregnancies at risk was carried out according to NAGLU activity on uncultured CV at 11th week or on cultured AF cell at 18th week of gestation.</p><p><b>RESULTS</b>The SGSH activities in leukocyte of normal controls were 4.4 - 8.1 nmol/(17 h.mg protein). The NAGLU activity in plasma of normal controls was 33.3 - 62.4 nmol/(4 h.ml). The NAGLU activities were 44.9 - 91.7 nmol/(17 h.mg protein) and 53.2 - 82.2 nmol/(17 h.mg protein) in CV and cultured AF cells respectively. Five cases of MPS IIIB and 7 cases of MPS IIIA were diagnosed. The mutation analysis of SGSH gene showed 6 mutations (G191R, D235N, R377C, E447K, R233X and D219Wfs264X), only one of which (D219Wfs264X) has not been previously reported. Prenatal diagnosis was performed on 3 pregnancies at risk. NAGLU activity of one affected fetus was 1.5 nmol/(17 h.mg protein) in AF cell.</p><p><b>CONCLUSIONS</b>The method using synthesized fluorigenic 4-methylumbelliferyl-substrates were sensitive, rapid and convenient assay of SGSH and NAGLU activity and were reliable for early prenatal diagnosis. Mutation analysis on MPS IIIA patients suggests new possibilities for molecular diagnosis of the disease.</p>

Clinical and molecular genetic study on two patients of the juvenile form of Pompe disease in China / 中华儿科杂志

<p><b>OBJECTIVE</b>Glycogen-storage disease type II (GSD II, Pompe's disease) is an autosomal recessive disorder caused by a functional deficiency of acid alpha-glucosidase (GAA) that leads to glycogen accumulation within lysosomes in most tissues. The GAA gene is located to human chromosome 17q25 and contains 20 exons, 19 of which are coding. Clinically, patients with the severe infantile form of GSD II have muscle weakness and cardiomyopathy eventually leading to death before the age of two years. Patients with the juvenile or the adult form of GSD II present with myopathy with a slow progression over several years or decades. A broad genetic heterogeneity has been described in GSD II in Europe, South Africa, USA, Japan and Korea, however, the investigation has not been performed in the patients from the mainland of China. In this study, clinical analysis and mutation detection were done on Chinese patients.</p><p><b>METHODS</b>Two unrelated juvenile patients with late onset GSD II (one boy, 3 years old and one girl, 9 years old) were included in the study with the informed consents. The diagnosis was confirmed by alpha-glucosidase determination in cultured fibroblasts. In addition, their clinical presentation, laboratory findings, electrophysiologic studies and muscle biopsy findings were analyzed in detail. Genomic DNA samples were extracted from fibroblasts of the probands, from peripheral blood of their parents and 50 unrelated, normal individuals. All the coding 19 exons and exon-intron boundaries of GAA were detected in the proband by polymerase chain reaction (PCR) and direct sequencing.</p><p><b>RESULTS</b>One patient presented decrease of muscle strength, limb-girdle hypotonia, the other patient presented reduced muscle volumes and respiratory problems. Both had increased CPK value, myopathic pattern on EMG; vacuoles on muscle biopsy, and deficiency of 1, 4-alpha-glucosidase activity. After 1 year follow up, the girl died after pneumonia at 10 years of age. One patient was found to be compound heretozygote for the novel mutation Arg702His, and the previously reported mutation Pro266Ser, which was reported in Korean population, with the late-onset phenotype. Two novel missense mutations Thr711Arg, Val723Met were found on the other patients.</p><p><b>CONCLUSIONS</b>Three mutations identified in the patient were new missense mutations causing late onset GSD II, which had not been reported elsewhere before.</p>

Analysis of ARSA mutations in a Chinese family with metachromatic leukodystrophy / 中华医学遗传学杂志

<p><b>OBJECTIVE</b>To identify arylsulftase A gene (ARSA) mutations in a Chinese family with MLD.</p><p><b>METHODS</b>There were two MLD patients in the investigated family. The proband, an 11-year-old girl, was well until the age of 5 years, when she began to experience difficult walking and mental regression. Magnetic resonance imaging (MRI) of her brain showed widespread demyelination, nerve conduction velocity reduced, and ASA activity measured in white blood cells was zero. So, the child was diagnosed having MLD. The proband's young brother also got the same phenotype except clinical symptom being milder than hers. Their parents and elder sister all had normal phenotypes. Genomic DNA samples were extracted from peripheral bloods of the proband and all her family members. All 8 exons and exon-intron boundaries of ARSA gene were amplified by polymerase chain reaction (PCR) and followed by direct DNA sequencing.</p><p><b>RESULTS</b>Two heterozygous mutations of ARSA, which were named as, G251A (R84Q) and G296T (G99V) were identified in the proband. The two mutations were located in exon 2. The same genotype was found in the proband's young brother, but these mutations were not detected in proband's elder sister. The proband's mother had the heterozygous mutations G296T (G99V), and her father had the heterozygous mutation G251A (R84Q).</p><p><b>CONCLUSION</b>These two MLD patients are with both compound heterozygous mutations, which mean one allele with the G296T (G99V) mutation was from their mother, and the other allele with the G251A (R84Q) mutation got from their father. The parents are both carrier with normal phenotype.</p>

Postnatal and prenatal diagnosis of mucopolysaccharidosis type II (Hunter syndrome) / 中华儿科杂志

<p><b>OBJECTIVE</b>Mucopolysaccharidosis type II (MPS II, Hunter syndrome, OMIM 309900) is an X-linked recessive lysosomal storage disease resulting from a deficiency of iduronte-2-sulphate sulphatase (IDS). The present study aimed to establish an enzyme assay method for IDS activity for carrying out postnatal and prenatal diagnosis of MPS II by means of IDS activity assay on plasma, uncultured chorionic villi (CV) and cultured amniotic fluid cells (AF cell) using a new synthesized substrate.</p><p><b>METHODS</b>A fluorigenic substrate (4-methylumbelliferyl-alpha-iduronate-2-sulphate, MU-alpha-Idu-2S) was used for the assay of IDS activity. IDS activity in plasma was determined for diagnosis of the proband. Prenatal diagnosis in 10 pregnancies at risk was carried out according to IDS activity on uncultured CV at 11th week or on cultured AF cell at 18th week of gestation. At the same time, IDS activity was also determined in the maternal plasmas to observe the change of IDS activity in pregnancy. The fetal sex determination was performed by PCR amplification of the ZFX/ZFY genes.</p><p><b>RESULT</b>The IDS activity in plasma of normal controls and obligate heterozygotes were 240.2 - 668.2 nmol/(4 hxml) and 88.7 - 547.9 nmol/(4 hxml), respectively, while the enzyme activities in plasmas were in the range of 0.3 - 18.6 nmol/(4 hxml) in affected male. The IDS activities were 37.2 - 54.9 nmol/(4 hxmg protein) and 21.4 - 74.4 nmol/(4 hxmg protein) in CV and cultured AF cells respectively. Out of 50 suspected cases, 46 were diagnosed as having MPS II and 4 were excluded. Prenatal diagnosis was performed on 10 pregnancies at risk. Four of 5 male fetuses [IDS activity were 4.7, 1.8, 7.0 nmol/(4hxmg protein) in CV, 0.6 nmol/(4 hxmg protein) in AF cell] were diagnosed as having MPS II and the other 5 fetuses were normal females [IDS activity were: 48.7, 5.9, 25.2 nmol/(4 hxmg protein) in CV, 55.2, 40.9 nmol/(4 hxmg protein) in AF cell]. Increased IDS activity was observed in plasma of the pregnant women with unaffected fetuses, while the IDS activity decreased in pregnancies with affected fetuses. IDS activity of one female fetus was very low [5.9 nmol/(4 hxmg protein)], but the IDS activity in maternal plasmas increased, this fetus was a normal female.</p><p><b>CONCLUSIONS</b>The method using a synthesized fluorigenic 4-methylumbelliferyl-substrate was a sensitive, rapid and convenient assay of IDS activity and was reliable for early prenatal diagnosis. Determination of fetal sex would be helpful in excluding the female fetus with low IDS activity from being considered as an affected male fetus. It would be further helpful if IDS activity in maternal plasma was taken into account.</p>

A retrospective study on enzyme replacement therapy in patients with Gaucher disease / 中华儿科杂志

<p><b>OBJECTIVE</b>Gaucher disease is the most common lysosomal storage disorder. A deficiency of beta-glucocerebrosidase causes accumulation of the glucocerebroside in macrophages throughout the body. This study summarizes the effects of enzyme replacement therapy (ERT) with Imiglucerase in children with Gaucher disease.</p><p><b>METHODS</b>Data from 72 patients (46 were male and 26 female, age ranged from 16 months to 22 years, median 8 years and 8 months) who were treated in the hospital between May 1999 and October 2005 were collected and analyzed, 57 of the patients had type 1 Gaucher disease, 2 patients with type 2, and 13 patients with type 3. Twenty-two patients had undergone total splenectomy. Imiglucerase was given at an initial dose 60 U/kg body weight by intravenous infusion every 2 weeks. The dose was reduced to 45 U/kg when they had achieved the specified therapeutic goals after 2 years. Clinical outcome data of Imiglucerase treatment were collected using routine Gaucher clinical measures, including growth, hematology, liver and spleen 3-dimensional measurements, and skeletal assessments every 3 - 6 months.</p><p><b>RESULTS</b>Three patients were lost to follow-up, 4 patients died, and 65 patients continued to receive the therapy. Hemoglobin and platelet levels of the patients with intact spleen increased most rapidly from the first 12 months of ERT (P < 0.01). Hemoglobin level of the patients who had undergone splenectomy determined at 30 months of treatment was higher than that of baseline (P < 0.01), but platelet levels were not significantly different (P > 0.05). The volumes of the liver decreased after the 6 months of ERT, decreased in average by (39 +/- 17)% at 24 months (P < 0.01). The volumes of spleen decreased after the 12 months of ERT by (59 +/- 21)% at 24 months (P < 0.01). During the first 12 month, the height and weight of the patients who were 2 - 12 years old increased (8.6 +/- 4.3) cm and (2.6 +/- 1.7) kg, respectively, and those of the patients who were 12 - 18 years old increased (5.2 +/- 3.9) cm and (4.5 +/- 3.3) kg, separately. Bone pain reported by 16 patients relieved after 3 months of treatment. But radiological evidence of bone disease did not change. The signs and symptoms of CNS involvement in patients with type 2 and type 3 disease were not improved. No serious adverse events were reported.</p><p><b>CONCLUSIONS</b>ERT with Imiglucerase could improve the quality of life of the patients with Gaucher disease by ameliorating the Gaucher disease-associated anemia, thrombocytopenia, organomegaly, growth retardation and bone pain.</p>

Whole-liver MR perfusion imaging in rabbit liver VX_2 tumors:early findings of coagulative necrosis after percutaneous ethanol injection therapy / 中华放射学杂志

Objective To investigate the value of whole-liver MR perfusion imaging(MRPI)for early detection of coagulative necrosis after percutaneous ethanol injection(PEI)in rabbit liver VX_2 tumors. Methods VX_2 tumor cell suspension was inoculated into rabbit liver and liver VX_2 tumors[diameter of (2.6?0.6)cm]were induced in 10 male rabbits.MR T_1 WI and T_2 WI were performed to monitor the development of the liver tumor on the 2~(nd)and 3~(rd)week after inoculation.Whole-liver MRPI was performed in the 10 rabbits with liver VX_2 tumors before and 6 days after PEI therapy(1.0 ml ethanol was injected into the most enhanced tumor region under CT guiding).Signal intensity(SI)values of untreated tumor parts and treated areas 6 days after PEI were recorded respectively.The steepest slope(SS)and bolus arrival time (TO)of SI-time curves were measured.The t-Student test was used in statistical analysis of the data.Results There was significant difference in MRPI data between untreated tumor parts[TO:(16.0?1.2)s and SS: 38.9?2.2]and treated areas[TO:(50.8?5.9)s and SS:6.0?1.2]6 days after PEI(t was 15.8 and -39.6 respectively,P