Clinico-pathological analysis of myelodysplastic syndromes according to French-American-British classification and international prognostic scoring system

INTRODUCTION

The aim of this study was to analyse the clinico-pathological features of a cohort of patients with myelodysplastic syndromes (MDS).

MATERIALS AND METHODS

The clinical and pathological data of 43 MDS patients over a 3-year period were reviewed. Survival analysis was performed according to the French-American-British (FAB) classification and International Prognostic Scoring System (IPSS) using the Kaplan-Meier method. Selected published studies for comparison were identified from MEDLINE search.

RESULTS

The patients were followed up for a median duration of 175 days (range, 2 to 1044 days). The median survival for refractory anaemia (RA) and refractory anaemia with ringed sideroblasts (RARS) has not been reached, but that for refractory anaemia with excess blasts (RAEB), refractory anaemia with excess blasts in transformation (RAEB-T) and chronic myelomonocytic leukaemia (CMML) was 250 days, 49 days and 44 days, respectively. The median survival for the low-risk and intermediate-1 IPSS categories has not been reached, while that for the intermediate-2 and high-risk categories was 58 days and 49 days, respectively. The survival analyses, according to the FAB classification and IPSS system, were statistically significant (P <0.05). Comparison of our data with those from neighbouring and Western countries revealed both similarity and disparity. We also noted different cytogenetic information in our cohort of patients.

CONCLUSIONS

We found distinctly unique cytogenetic and clinico-pathological characteristics in our MDS patients. However, whether true biological differences exist among MDS patients in different geographies and populations with different genetic and environmental backgrounds require further large multinational study.

Gene frequencies of the HPA-1 to HPA-13, Oe and Gov platelet antigen alleles in Taiwanese, Indonesian, Filipino and Thai populations

Human platelet antigen (HPA) systems consist of more than twelve bi-allelic antigen polymorphisms in which a base pair substitution leads to change in an amino acid of a glycoprotein expressed on the platelet. The neonatal alloimmune thrombocytopenia (NAIT), post transfusion purpura, and refractoriness to platelet transfusion can be induced by antibodies against human platelet antigens: e.g. HPA-1a, 3a, 4a, 5a, and Gova. HPA typing is essential for the diagnosis and treatment of a variety of diseases. We developed a PCR-based method to detect HPA-1 to HPA-13, Oe and Gov platelet alloantigens. In this method, the amplified PCR products were used to recognize the polymorphism after restriction enzyme digestions. Among 566 Taiwanese, 107 Indonesian, 100 Filipino and 137 Thai subjects studied, HPA-1a, 2a, 4a, 5a, 6a, 7aW, 8aW, 9a, 10a, 11a, 12a, 13a, Oea genes were present in every sample; while HPA-1b, 2b, 4b, 5b and 6b were rarely found. HPA-7aW, 8aW, 9, 10, 11, 12, 13, and Oea alleles were noted to be monomorphic only. HPA-3a/3b alleles had frequencies of 0.595/0.405, 0.505/0.495, 0.507/0.493, 0.530/0.470, while Gova/Govb of 0.462/0.538, 0.450/0.550, 0.463/0.537, 0.520/0.480 among Taiwanese, Indonesians, Thais and Filipinos respectively. The prevalence rates of HPA-1 to 13 in this study were also consistent with other previous reports using different methods. The alloimmunization due to Gov and HPA-3 antigens need to be emphasized in these populations.

External quality assurance schemes in flow cytometry

Quality assurance schemes were devised to monitor the performance of laboratory tests commonly utilized in routine clinical practice. In the area of Flow Cytometry, external quality assurance schemes are very much in their infancy. There are 3 major applications of Flow Cytometry in the clinical laboratory: lymphocyte subset enumeration, CD34 enumeration and leukemia immuno-phenotyping. Pilot schemes for CD34 enumeration and leukemia immuno-phenotyping have revealed a considerable lack of consensus with a wide divergence in practices. The coefficient of variation in reported results from these assessments have been very large, ranging from 20-200%. Results for lymphocyte subset enumeration surveys are sometimes not much better despite having been around for a longer period of time. Quality assurance programs in Flow Cytometry are difficult to conduct and 3 or 4 concurrent factors are often cited as reasons for the large variability. The need for viable, functionally intact cells as suitable assay material is probably the biggest contributor to the large variability. This difficulty in providing stable cells for inter-laboratory comparison is compounded by the lack of consensus in testing methodology. Participation in a distant external quality assurance scheme is consequently not very helpful to improving the practices in the laboratory. Currently, there are more problems than solutions. An awareness of these issues will hopefully contribute to the development of future consensus and offer up solutions to some of these problems.

Gene frequencies of the HPA-1 to HPA-8w platelet antigen alleles in Taiwanese, Indonesian, and Thai

Human platelet antigen (HPA) systems consist of more than eight biallelic antigen polymorphisms in which a base pair substitution leads to change in an amino acid of a glycoprotein expressed on the platelet. HPA typing is essential in the diagnosis and treatment for a variety of diseases. We developed a polymerase chain reaction (PCR)-based method to detect HPA-1 through HPA-8w. In this method, the amplified PCR products were used to recognize the polymorphism after restriction enzyme digestions. Among 295 Taiwanese, 107 Indonesian, and 137 Thai subjects studied, HPA-1a, 2a, 4a, 5a, 6a, 7aw, and 8aw genes were present in every sample tested. HPA-1b, 2b, 4b, 5b, and 6b were rarely found among subjects. Only monomorphic HPA-7aw and 8aw alleles were noted in the samples. HPA-3a and 3b alleles showed frequencies of 0.595/0.405, 0.504/0.496, and 0.507/0.493 in Taiwanese, Indonesian, and Thai subjects, respectively. Our report is the first PCR-based method to detect most of the HPA antigen variants in Taiwanese, Indonesian, and Thai. The genomic typing results were also confirmed by direct sequencing for uncertain and some representative cases. The prevalence rates of HPA-1, 2, 3, 4, and 5 in this study were also consistent with other previous reports using different methods.

Autologous peripheral blood stem cells harvesting in Kaohsiung Medical University Hospital

We report our clinical experience in autologous peripheral blood stem cells harvesting. A total of 40 patients with 112 apheresis procedures were analyzed, 88 with Cobe system and 24 with MCS3P system. Our results revealed that there was no significant difference in efficiency of CD34(+) cell harvesting between both apheresis systems, but the Cobe system had more nucleated cells collected and less red cell contaminated in the final PBSCs collections. The percentage of CD34(+) cells collected decreased significantly following the first day's harvesting (p = 0.026). There was a good correlation between the percentage of CD34(+) cells in PBSCs and colony forming units-granulocyte macrophage (CFU-GM) or burst forming unit-erythrocyte (BFU-E)(r = 0.909, p < 0.0001; r = 0.788, p < 0.0001, respectively). However, it was negatively correlated with the patient's age. The CD34(+) cells collected in patients with acute leukemias were also higher than those patients with other solid tumors. Ten cases (13%) with 15 apheresis procedures experienced side effects like numbness, nausea, fever, or headache etc. The Cobe system seemed to have higher frequency of side effects than that of MCS3P system (16% vs 4%). From our results, we concluded that both COBE and MCS3P system have similar efficiency and all patients could tolerate the apheresis procedures in peripheral blood stem cells harvesting. The CD34(+) cell can be used as a good parameter to estimate the amount of stem cells collected. The patient's age and disease pattern were significant factors influencing the CD34(+) stem cells collection in autologous peripheral blood stem cells harvesting.

A molecular genetic analysis of the Kidd blood group polymorphism in Taiwanese, Thais, and Filipinos

In this study, we molecularly detect the Jka/Jkb polymorphism in Taiwanese, Thais, and Filipinos with PCR-restriction enzyme digestion. We designed the primers with mutagenic bases to create two restriction enzyme cutting sites (EcoN I and Xba I) simultaneously to confirm the genetic polymorphism of Jka/Jkb. One hundred and seven unrelated Taiwanese, 107 Thais foreign laborers, and 102 Filipino foreign laborers in Taiwan were analyzed. The frequency of Jka and Jkb is 0.51 and 0.49 in Taiwanese, 0.44 and 0.56 in Thais, and 0.45 and 0.55 in Filipinos, respectively. The molecular analysis of Jka/Jkb polymorphism is simple, accurate and could confirm the uncertain results obtained by serological typing. The method could be used for predicting fetal Kidd genotype from amniocyte DNA, and to avoid the hemolytic disease of newborns caused by Jk antibody.

Signal transduction pathways involved in low intensity He-Ne laser-induced respiratory burst in bovine neutrophils: a potential mechanism of low intensity laser biostimulation

BACKGROUND AND OBJECTIVE

Low intensity He-Ne laser irradiation has been reported to induce respiratory burst of neutrophils for a long time, but the mechanism remains obscure. We speculated that it is mediated by some signal transduction pathways.

STUDY DESIGN/MATERIALS AND METHODS

The protein tyrosine kinases (PTKs) inhibitor, genistein, the phospholipase C (PLC) inhibitor, U-73122, and the protein kinase C (PKC) inhibitor, calphostin C, were used to probe signal transduction pathways of respiratory burst of bovine neutrophils which were induced by He-Ne laser at a dose of 300 J/m(2), respectively.

RESULTS

The inhibitor of PTKs can completely inhibit the He-Ne laser-induced respiratory burst of neutrophils. PLC and PKC inhibitors can obviously reduce it, but not fully inhibit it.

CONCLUSION

These results suggest that PTKs play a key role in the He-Ne laser-induced respiratory burst of neutrophils and [PTK-PLC-PKC-NADPH oxidase] signal transduction pathways may be involved in this process.

CD34+ stem cell transplantation in malignancies: report of three cases

Purging tumor cells from peripheral blood stem cells (PBSCs) used to treat patients with malignancy is important in the prevention of relapse. Positive selection of CD34+ stem cells using either immunomagnetic methods or an avidin-biotin conjugated CD34 monoclonal antibody binding column can reduce the number of contaminating tumor cells. We describe the management of three patients with malignancy treated using high-dose chemotherapy and enriched CD34+ cell transplantation. PBSCs were mobilized with cyclophosphamide plus recombinant granulocyte-colony stimulating factor (rG-CSF), and then leukophoresis was performed to harvest the PBSCs. The collected cells were positively selected for CD34+ cells using the Cellpro system. The CD34(+)-enriched PBSCs were then cryopreserved in the vapor phase of liquid nitrogen for future reinfusion. All three patients recovered smoothly after transplantation. The mean time to full hematologic recovery was 12 days for white blood cells (> or = 1 x 10(9)/L) and 14 days for platelets (> or = 20 x 10(9)/L), respectively. Partial remission occurred in two patients who were disease free for more than 4 years, and in one patient who died of hepatic failure with liver cirrhosis 5.5 months posttransplantation.

Prenatal diagnosis of der(11)t(11;18)(q24;q21.3) due to paternal balanced translocation and both parents are carriers of alpha-thalassemia-1--a case report

A couple were identified as alpha-thalassemia-1 carriers (father: alpha-thal-1 of Filipino type, mother: alpha-thal-1 of SEA type). Amniocentesis was done at 19 weeks of gestation by a local obstetrician. Molecular study of amniotic fluid presented a non-thalassemia fetus, but the cytogenetic study revealed a karyotype of 46,XX,der(11)t(11;18)(q24;q21.3), resulting from a paternal balanced reciprocal translocation and unbalanced adjacent 1 segregation. The pregnancy was terminated at 23 weeks of gestation. The gross of fetus revealed bilateral cleft lip and palate, hypertelorism, flat nasal bridge, frontal bossing, micrognathia, low set ears, short neck with cystic hygroma, overlapping fingers, prominent heels, and limited hip abduction. The chromosome complement of the present case was partial monosomy for 11q24-qter and partial trisomy for 18q21.3-qter. This is the first prenatal diagnosis of unbalanced translocation with der(11)t(11;18)(q24;q21.3) pat due to paternal balanced translocation and both parents being carriers of alpha-thalassemia-1.

Beam propagation of x rays in a laser-produced plasma and a modified relation of interferometry in measuring the electron density

In this paper, using a quantum mechanical technique and introducing the so-called V representation (where the representation transformation is made by using the potential Hamiltonian V), we studied x-ray propagation in a linear plasma medium both analytically and numerically. A modified relation between the phase of the probe and the reference light and the electron density of the plasma is derived, in which the contribution of the gradient of the electron density has been taken into account. It is shown that this relation has the advantage in measurements of the electron density of a plasma using the x-ray interferometry technique of lessening the errors originating from the electron density gradient. The validity of x-ray interferometry is discussed in both mathematical and physical terms.

Secondary chronic myelogenous leukemia after autologous peripheral blood stem cell transplantation for Lymphoma

A 31-year-old woman was diagnosed with intestinal lymphoma (high-grade mucosa-associated lymphoid tissue lymphoma, stage IIE) in September 1996. Eleven courses of chemotherapy were administered, but the results were poor. She received autologous peripheral blood stem cell transplantation (PBSCT) in September 1997. Leukocytosis was noted, and chronic myelogenous leukemia was diagnosed 8 months after the PBSCT, progressing to blast phase 10 months later. We report this case because secondary chronic myelogenous leukemia after stem cell transplantation is rare.

Lewis (FUT3) genotypes in Taiwanese, Thai, and Filipino populations

The Lewis (Le) blood type comprises two major antigens, Le(a) and Le(b), which are encoded by alpha (1,2)-fucosyltransferase (FUT2) and a (1,3/1,4)-fucosyl-transferase (FUT3). In this study, we analyzed the mutations of FUT3 in Taiwanese, Thai, and Filipino populations and correlated these with serologic phenotypes. One hundred and thirty-seven Taiwanese, 71 Thai, and 125 Filipino were studied unselectively. The frequency of the normal and four other mutant alleles for Taiwanese, Thai, and Filipino, respectively, were as follows: 187/274 (68.2%), 87/142 (61.3%), and 160/250 (64.0%) were wild type (Le); 14/274 (5.1%), 1/142 (0.7%), and 1/250 (0.4%) were a T202C/C314T mutation (le202,314); 35/274 (12.8%), 15/142 (10.6%), and 22/250 (8.8%) had the G508A mutation (le508); and 38/274 (13.9%), 39/142 (27.4%), and 67/250 (26.8%) carried the T1067A mutation (le1067). The le445 and le1007 were not detected in this study. Our result provided the first genetic data of the FUT3 gene in these three populations, and the frequency distribution of mutant alleles among Taiwanese, Thai, and Filipinos demonstrates a significant difference (P<0.001). In our study, the le202,314 mutation had considerable frequency in the Taiwanese, but the le1067 mutation had a higher frequency in Thai and Filipinos.

Molecular basis of Lewis blood type in Taiwanese

The Lewis (Le) histo-blood group system comprises two major antigens, Le(a) and Le(b) which are determined by alpha (1,2)-fucosyltransferase (FUT2) and alpha (1,3/1,4)-fucosyltransferase (FUT3). In this study, we analyzed the mutations of FUT2 and FUT3 genes in 101 Taiwanese by molecular biology method and compared them with their serologic phenotypes to explore their relationship. There is at least one wild allele of FUT2 and FUT3 genes in phenotype of Le (a-b+). The phenotypes of Le (a+b-) and Le (a+b+) are caused by mutations of both alleles of FUT2 gene and at least one wild allele of FUT3 gene. The genotypes of Le (a+b-) and Le (a+b+) are the same. Twenty cases are phenotype of Le (a-b-), which are caused by mutations of both alleles of FUT 2 gene and/or FUT 3 gene. Twelve cases were caused by both alleles mutations of FUT 3 gene only, while three cases were caused by mutations of both alleles of FUT2 gene and the rest of the cases were caused by mutations of both alleles of FUT2 and FUT3 genes. Our findings confirm that the Le histo-blood group is determined by the interaction of FUT 2 and FUT 3 genes. Our report is the first study of FUT 2 gene and FUT 3 gene in a Taiwanese population. We suggest that the genetic analysis of Le blood group should include FUT 2 and FUT 3 genes together.

Aging and external ear resonance

External ear resonance was measured in elderly people using a probe-tube microphone system. Resonance frequency, amplitude, and bandwidth as well as ear canal volume were compared across age groups and genders. No significant age group trends were observed in external ear resonant frequency. Also, the amplitude and bandwidth of the resonance peaks across ages were not significantly different. For the gender effect, the mean external ear resonant frequencies are generally higher for females than for males in all age groups, but the differences are not statistically significant. The mean amplitudes of the resonant frequency are larger for men than for women. But the difference is also small. For the ear canal volume, no significant age trend was found. However, the mean ear canal volume was significantly larger for males than for females.

Cloning and expression of ZAK, a mixed lineage kinase-like protein containing a leucine-zipper and a sterile-alpha motif

A novel mixed lineage kinase-like protein ZAK, containing a leucine-zipper (LZ) and a sterile-alpha motif (SAM), was cloned. This cDNA has 2456 bp and encodes a protein of 800 amino acids that contains a kinase catalytic domain, a leucine-zipper and a SAM. The molecular weight of this protein is 91kDa. Northern blot analysis revealed that the expression of this ZAK gene is found in various parts of human tissues. We also found that ZAK proteins might form homodimers or oligomers in mammalian cells. MLKs have been proposed to function as mitogen-activated protein kinase kinase kinase in pathways leading to MAPK cascade. The expression of ZAK in mammalian cells specifically leads to the activation of the JNK/SAPK pathway as well as the activation of transcription factor, NF-kappaB. Overexpression of the ZAK gene induces the apoptosis of a hepatoma cell line.

Myelodysplastic syndrome with monosomy 7 and pulmonary aspergillosis

A 43-year-old man with no past history presented with symptoms of fever, cough and dyspnoea arising from invasive pulmonary aspergillosis and was found to have myelodysplastic syndrome with monosomy 7. Before initiation of chemotherapy, he deteriorated rapidly, developing multi-organ failure requiring mechanical ventilation, and he eventually succumbed despite amphotericin B treatment. The importance of monosomy 7 in determining immune function in patients with myelodysplastic syndrome is emphasised.

Histological rearrangement in the facial nerve and central nuclei following immediate and delayed hypoglossal-facial nerve anastomosis

The timing of hypoglossal-facial nerve anastomosis is controversial. The present study was performed to clarify the influence of the timing of hypoglossal-facial nerve anastomosis on histological changes in the facial nerve and central nuclei using guinea pigs. The facial nerve was transected first at the labyrinthine portion, and then transected again at the stylomastoid foramen. Hypoglossal-facial nerve anastomosis was carried out immediately or 3 months later. Nerve regeneration and survival of the neurons in the facial and hypoglossal nuclei were evaluated by toluidine blue staining and horseradish peroxidase (HRP). Immediate anastomosis resulted in better nerve regeneration of the facial nerve, but the numbers of surviving neurons in the facial and hypoglossal nuclei were almost the same in both the immediate and delayed anastomosis groups.

Mutation analysis of PTEN/MMAC1 in acute myeloid leukemia

Recently, a putative tumor suppressor gene, PTEN/MMAC1, has been identified at chromosome 10q23.3, which encodes a 403 amino acid dual-specificity phosphatase containing a region of homology to tensin and auxillin. Somatic mutations of the PTEN/MMAC1 gene have been identified in a number of cancer cell lines and primary cancers. Mutations in PTEN/MMAC1 are most frequently found in advanced cancers. To evaluate the role of the PTEN/MMAC1 gene in leukemia, bone marrow and/or peripheral blood from 62 acute myeloid leukemia (AML) patients, 5 hemopoietic cell lines (HL60, U937, Raji, KG-1, K562), and 30 normal controls were analyzed. The results showed aberrant PTEN/MMAC1 transcripts in 15 of the 62 (24%) AML patients, 4 of the 5 cell lines (80%), and 4 of the 30 (13%) normal controls. As in our previous study of TSG101, the abnormal transcripts may result from aberrant RNA splicing as evidenced by the presence of both these aberrant transcripts and normal full length transcripts in all specimens examined. Loss of heterozygosity (LOH) analysis and PCR-SSCP of the entire coding region showed that none of the AML cases had LOH or mutation. Only one frameshift mutation at codon 130 (insertion of CCCG) with premature termination of coding sequence was observed in the U937 cell line. Our results indicate that the PTEN/MMAC1 gene may play a role in a small percentage of AML, but its significance needs to be further evaluated.

Activities of Na(+),K(+)-ATPase and Ca(2+)-ATPase in cochlear lateral wall after acoustic trauma

Na(+),K(+)-ATPase and Ca(2+)-ATPase are well known participants in the active transport of ions in the inner ear. These two enzymes play an important role in maintaining cochlear function. Although changes in these enzymes' activities in the cochlea have been implicated in noise-induced hearing loss, no evidence of quantitative alteration of Na(+),K(+)-ATPase or Ca(2+)-ATPase activities has ever been shown. The present study was undertaken to determine the quantitative alterations of their activities by microcolorimetric assay in the cochlear lateral wall after acoustic trauma. Adult albino guinea pigs were exposed to white noise at 105+/-2 dB A for 10 min or 40 h. The age-matched control animals were not exposed to noise. Noise exposure resulted in a significant threshold shift of the auditory brainstem response (P<0.001). Significant decreases in activities of Na(+),K(+)-ATPase and Ca(2+)-ATPase were found in the cochlear lateral wall after noise exposure (P<0.001). Statistical analysis indicated that a good correlation held not only between the decline of these enzyme activities and noise-induced hearing loss, but also between the gradual partial recovery of these parameters during the first 10-day recovery period. The present findings suggest that metabolic damage and ionic disturbance may contribute, at least partially, to noise-induced hearing threshold shift.

Loudness discomfort levels in patients with conductive and mixed hearing loss

OBJECTIVE

The purpose of this study is to investigate the effects of conductive component on the loudness discomfort level (LDL) judgments. The relation between LDL value and the magnitude of air-bone gap in such subjects was also assessed.

METHODS

LDLs were obtained from 100 ears of 50 hearing-impaired subjects. Twenty five subjects (50 ears) had either conductive or mixed hearing loss for both ears. Another 25 subjects (50 ears) with bilateral sensorineural hearing loss served as control. LDL measurements were performed using the method reported by Hawkins et al. in 1987. LDL data were plotted and analyzed as a function of hearing loss for three stimulus frequencies (0.5, 1.0 and 2 kHz). Also, LDL values were plotted as a function of air-bone gap in the conductive group.

RESULTS

LDLs were significantly higher in subjects with conductive or mixed hearing loss for all three tested frequencies. There is a significant positive correlation between LDL value and the magnitude of air-bone gap for all three test frequencies. Considerable intersubject variability was found in LDLs obtained from subjects with conductive component which prevented the accurate prediction of LDLs from threshold data for such patients.

CONCLUSION

The large intersubject variation in LDL data strongly suggests the need for individualized LDL measurements in patients with conductive or mixed hearing loss. Higher LDLs indicates that higher maximal power output can be prescribed for such patients without worrying about loudness intolerance.

Probe-tube microphone measures in patients with open-mastoid surgery: real-ear-to-coupler differences and real-ear unaided responses

Real-ear-to-coupler differences (RECDs) and real-ear unaided responses (REURs) were measured using a probe-tube microphone system in 15 patients who underwent open mastoid surgery. The results show that RECDs are significantly smaller at higher frequencies (1.5, 2.0, 3.0, 4.0 and 6.0 kHz) in mastoid ears. The intrasubject variability of RECDs measures in these patients is on average 2.6 dB larger than for controls. For REURs, mastoid surgery significantly reduced the mean peak resonant frequency without affecting the amplitude and bandwidth. In operated ears, mean resonant frequency is by a factor of 1.4 lower than that for normal ears. Reduced responses (negative gains) at frequencies above the resonance peak occurred in 7 out of the 15 patients. These reduced responses corresponded to the smaller RECD at the middle and high frequencies. The results support the need for individual RECD measures to be made in operated ears instead of using average values from normal subjects. Otherwise, real-ear measures of the aided response should be made for each patient with open-mastoid cavity and the fitting should be done in terms of the target response at the eardrum rather than by defining a target insertion gain.

Tone detection in Mandarin-speaking hearing-impaired subjects

The ability of native Mandarin-speaking, hearing-impaired subjects to detect Mandarin tones was assessed in this study. Nine subjects with mild sensorineural hearing loss (SNHL) and nine subjects with moderate SNHL participated in the study. Nine normal subjects served as control. All subjects received a tone detection test and Chinese word recognition test. The results show that tone detection was only minimally impaired in the mild SNHL group if audibility of the stimulus is well compensated for. In the moderate SNHL group, the mean score was significantly lower, but the difference was small. This suggests that tone detection is only slightly impaired for subjects with moderate hearing loss. For each individual tone, the mean scores for tones 2 and 3 were lowest and most easily confused by all normal and hearing-impaired subjects. No significant correlation was found between the tone detection score and word recognition score for all subjects. The relatively preserved ability to perceive tones in mild and moderate SNHL subjects may be helpful in their speech recognition.

Clinical implications of aberrant TSG101 transcripts in acute myeloblastic leukemia

Tsg101 is a mouse tumor suppressor gene whose homozygous deletion produces transformation of NIH3T3 cells and leads to metastases in nude mice. The human homologue of the gene, TSG101, is localized in chromosome 11p15.1-p15.2. Reduced TSG101 expression may cause the defect of the cell cycle checkpoint that leads to genetic instability and consequently to the progression of neoplasia. Aberrant TSG101 transcript have been identified in many types of cancers, and the relaxation of RNA splicing fidelity may be an onco-developmental marker in cancers and could play a general role in tumorigenesis. In our previous study, smaller TSG101 transcripts were found in AML specimens, hematopoietic cell lines and normal controls. The aberrant transcripts occurred more frequently in the AML cases and cell lines. The patients with aberrant TSG101 transcripts had higher initial white cell count, lower LDH level, and lower complete remission rate after induction chemotherapy. However, further multivariate analysis of clinical data revealed that there was no relationship to the TSG101 aberrant transcripts. The clinical significance of TSG101 aberrant transcript in AML needs further evaluation.

Mutation analysis of PTEN/MMAC 1 in sporadic thyroid tumors

Recently, a putative tumor suppressor gene, PTEN/MMAC1, has been identified at chromosome 10q23.3. This gene encodes a 403 amino acid dual specificity phosphatase containing a region of homology to tensin and auxillin. Somatic mutations of the PTEN/MMAC1 gene have been found in a number of cancer cell lines and primary cancers. Cowden disease, an autosomal dominant harmartoma syndrome associated with thyroid and breast tumors, has been found to be associated with mutations of PTEN/MMAC1 gene. To evaluate the role of the PTEN/MMAC1 gene in sporadic thyroid tumors, we studied 17 sporadic thyroid tumors, of which 12 were papillary thyroid carcinomas, 1 was follicular thyroid carcinoma, 1 was medullary thyroid carcinoma and 3 were thyroid adenomas. Direct sequencing of PCR-amplified products was performed for all nine exons of PTEN/MMAC1. No mutations of PTEN/MMAC1 gene were observed in any of the sporadic thyroid tumors. Our results indicate that the PTEN/MMAC1 gene may not play a major role in sporadic thyroid tumors.