Treatment Patterns and FLT3 Mutation Testing Among Patients with Acute Myeloid Leukemia in China: A Retrospective Observational Study.

Introduction: For acute myeloid leukemia (AML), prognosis is particularly poor in patients harboring FMS-like tyrosine kinase 3 (FLT3) gene mutations, though routine screening for these mutations at diagnosis has been shown to be insufficient. The understanding of the impact of FLT3 mutations on treatment decisions is limited. Methods: In this retrospective, observational study, we investigated the key epidemiological characteristics, treatment patterns and responses among adult patients with newly diagnosed (ND) AML in China, who initiated treatment from January 1, 2015, to December 31, 2019, or progressed to relapsed/refractory (R/R) AML by December 31, 2020. Results: Of the 853 ND AML patients included, 63.4% were screened for FLT3 status, and 20.1% tested positive (FLT3MUT) at initial diagnosis. Of 289 patients who progressed to R/R AML during the study period, 24.9% were screened at the diagnosis of R/R AML, and 19.4% tested positive; 20.5% of screened patients changed FLT3 status at first diagnosis of R/R AML. Initial treatment regimens or treatment responses did not seem to differ in patients with ND AML by FLT3 mutation status. In patients with R/R AML, there was an apparent difference in second-line treatment choices by FLT3 mutation status; however, the number of FLT3-mutated patients were limited to demonstrate any meaningful distinction. FLT3-mutated R/R AML was associated with shorter relapse time. Conclusion: Study findings showed that there was a lack of routine testing for FLT3 mutations at first diagnosis of R/R AML, and initial treatment decisions did not differ by FLT3 mutation status. Given the clinical burden of FLT3MUT, likelihood of FLT3 status changes, and emerging FLT3 inhibitors, further routine FLT3 screening is needed to optimize treatment of R/R AML.

Pediatric-inspired regimen for adolescent and adult patients with Philadelphia chromosome-negative acute lymphoblastic leukemia: a prospective study from China.

Several international centers have used and reported pediatric-inspired regimens for adolescent and adult patients with Philadelphia chromosome-negative acute lymphoblastic leukemia (Ph- ALL). However, there is a lack of prospective data on the Chinese population. Herein, we performed a prospective study with a pediatric-inspired regimen (IH-2014 regimen) in treating adolescent and adult Ph- ALL patients in our center. From 2014 to 2021, a total of 415 patients aged between 14 and 65 years (median age, 27) were included in this study. After a median follow-up of 40.8 months, the 5-year overall survival, disease-free survival, and event-free survival rates were 53.8%, 51.1% and 45.0%, respectively. The regimen was generally well tolerated and safe, and the overall chemotherapy-related mortality was 3.6%. Age ≥ 40 years and persistent detectable minimal residual disease (MRD) post-induction were independent prognostic factors. Traditional risk factors for adult patients combined with MRD post-induction exhibit predictive significance for survival and relapse, which is helpful in the selection of subsequent treatment. Patients with high risk factors who can achieve deep MRD response after induction do not derive benefit from allogeneic hematopoietic stem cell transplantation.

RBFOX2 confers tumor growth by PI3K/AKT and MAPK signaling in gastric cancer.

RNA-binding Fox (RBFOX)2, a member of a family of RNA-binding proteins, is well known as a regulator of alternative pre-mRNA splicing. However, its possible role in gastric cancer is unknown. In this study, we investigated the biologic role and clinical significance of RBFOX2 in gastric cancer growth and elucidated its underlying molecular mechanisms. We found that RBFOX2 was highly expressed in gastric cancer cell lines and tumor tissue compared with the adjacent nontumor tissue. We also found that RBFOX2 overexpression was correlated with poor overall survival in patients with gastric cancers. Multivariate survival analyses revealed that higher RBFOX2 expression was an independent prognostic factor for the overall survival of patients with gastric cancers. Suppression of RBFOX2 by shRNA inhibited gastric cancer cell proliferation, colony formation and induced apoptosis. Mechanism studies revealed that these effects were achieved through the simultaneous modulation of multiple signaling pathways. Knockdown of RBFOX2 expression by shRNA markedly inhibited the phosphorylation of phosphatidylinositol 3-hydroxy kinase, threonine kinase and extracellular signal-regulated kinase and Jun N-terminal kinases proteins. In contrast, the ectopic expression of RBFOX2 had the opposite effects. Moreover, RBFOX2 knockdown also induced the cleavage of caspase-3 and caspase-9 proteins. Collectively, these results demonstrate that RBFOX2 plays a critical role in regulating gastric cancer cell proliferation and survival and may be a potential prognostic biomarker and therapeutic target for gastric cancer.

Correlation between methylation level of the SLC19A1 promoter region and methotrexate metabolism in adult acute lymphoblastic leukemia.

Aims: To analyze the methylation level in the promoter region of SLC19A1 in adult acute lymphoblastic leukemia (ALL) patients, and explore the relationship between methotrexate (MTX) drug metabolism and SLC19A1 methylation. Methods: The methylation levels of the SLC19A1 promoter region in 52 adult ALL patients who received high-dose MTX chemotherapy were retrospectively analyzed in combination with clinical indicators and plasma MTX concentration. Results: Methylation levels of 17 CpG units were differently correlated with clinical parameters of ALL patients including gender, age, immunophenotype and Philadelphia chromosome status. Patients with delayed MTX drug excretion had higher methylation levels in the SLC19A1 promoter region. Conclusion: The methylation may affect the MTX plasma level and adverse reactions, which may predict patients at risk of adverse reactions after high-dose MTX therapy.

Effects of genetic polymorphisms on methotrexate levels and toxicity in Chinese patients with acute lymphoblastic leukemia.

Methotrexate (MTX) has an antitumor effect when used for the treatment of acute lymphoblastic leukemia (ALL). This study aims at evaluating the associations between 14 polymorphisms of six genes involved in MTX metabolism with serum MTX concentration and toxicity accompanying high-dose MTX. Polymorphisms in 183 Chinese patients with ALL were analyzed using TaqMan single nucleotide polymorphism genotyping assay. The serum MTX concentration was determined using homogeneous enzyme immunoassay. MTX-related toxicities were also evaluated. Renal toxicity was significantly associated with higher serum MTX concentrations at 24, 48, and 72 hours, and MTX elimination delay (P = 0.001, P < 0.001, P < 0.001, and P < 0.001, respectively), whereas SLCO1B1 rs4149056 was associated with serum MTX concentrations at 48 and 72 hours, and MTX elimination delay in candidate polymorphisms (P = 0.014, P = 0.019, and P = 0.007, respectively). SLC19A1 rs2838958 and rs3788200 were associated with serum MTX concentrations at 24 hours (P = 0.016, P = 0.043, respectively). MTRR rs1801394 was associated with serum MTX concentrations at 72 hours (P = 0.045). Neutropenia was related to SLC19A1 rs4149056 (odds ratio [OR]: 3.172, 95% confidence interval [CI]: 1.310-7.681, P = 0.011). Hepatotoxicity was associated with ABCC2 rs2273697 (OR: 3.494, 95% CI: 1.236-9.873, P = 0.018) and MTRR rs1801394 (OR: 0.231, 95% CI: 0.084-0.632, P = 0.004). Polymorphisms of SLCO1B1, SLC19A1, ABCC2, and MTRR genes help predict higher risk of increased MTX levels or MTX-related toxicities in adult ALL patients.

Prognostic significance of copy number variation in B-cell acute lymphoblastic leukemia.

Copy number variations (CNVs) are widespread in both pediatric and adult cases of B-cell acute lymphoblastic leukemia (B-ALL); however, their clinical significance remains unclear. This review primarily discusses the most prevalent CNVs in B-ALL to elucidate their clinical value and further personalized management of this population. The discovery of the molecular mechanism of gene deletion and the development of targeted drugs will further enhance the clinical prognosis of B-ALL.

A short report of novel RARG-HNRNPM fusion gene in resembling acute promyelocytic leukemia.

BACKGROUND: Resembling acute promyelocytic leukemia (APL) is a unique subtype of APL who sharing clinical, morphological, and immunophenotypic features with typical APL, but lacking evidence of PML-RARA fusion gene and usually insensitive to arsenic trioxide (ATO) and all-trans retinoic acid (ATRA). For years, RARA, RARB and RARG rearrangement were found in resembling APL continually. The confirmed partner genes of RARG rearrangement included CPSF6, NUP98, NPM1, PML, and HNRNPC. These patients were a group of resembling APL with rare molecular genetic abnormality and unfavorable prognosis. They usually were resistant to ATO and ATRA but partially sensitive to anthracycline-based chemotherapy. CASE PRESENTATION: We reported a 25-year-old female patient with a novel fusion gene RARG-HNRNPM (RARG chr12:53606869: -; HNRNPM chr19: 8527413: + based on GRCh37/hg19 Assembly) through RNA-seq as resembling APL. The patient with RARG-HNRNPM was benefited from a combined chemotherapy homoharringtonine, cytarabine, and aclacinomycin (HAA) regimen with no relapse. DISCUSSION AND CONCLUSIONS: RARG rearrangement resembling APL are various. The treatment should be switched from ATRA/ATO to AML combined chemotherapy regimen early.

The clinical characteristics and prognosis in adult Ph negative acute lymphoblastic leukemia with TP53 aberrations.

Very few reports elucidate the prognosis of patients with TP53 aberrations using both measurable residual disease (MRD) and the status of having undergone allogeneic hematopoietic stem cell transplantation (allo-SCT). In this study, aberrations of TP53 were analyzed using next-generation sequencing (NGS) and fluorescence in situ hybridization (FISH) in patients with Philadelphia chromosome-negative (Ph-) ALL enrolled in a prospective single-arm clinical trial at our leukemia center. We analyzed the survival of the patients grouped according to the MRD level at the third month and whether or not received allo-SCT. We found that allo-SCT could improve the OS in patients with TP53 aberrations; Patients having negative MRD at the third month still showed worse 3-year OS and 3-year DFS without undergoing allo-SCT, which is different from previous studies, moreover, the prognostic significance of TP53 deletions was as important as TP53 mutations, the importance of screening both TP53 deletions and mutations in adult Ph- ALL at diagnosis should be emphasized.

The prognostic factors in acute myeloid leukaemia with double-mutated CCAAT/enhancer-binding protein alpha (CEBPAdm).

The prognostic factors to stratify acute myeloid leukaemia (AML) with double-mutated CCAAT/enhancer-binding protein alpha (CEBPAdm) into different risk groups remains to be determined. In this retrospective study, we evaluated 171 consecutive patients with newly diagnosed AML with CEBPAdm by a Cox proportional hazards regression model. In univariate analyses, colony stimulating factor 3 receptor (CSF3R) and Wilms tumour 1 (WT1) mutations were associated with poor relapse-free survival (RFS). The induction regimens including homoharringtonine (omacetaxine mepesuccinate) or intermediate-dose cytarabine was associated with favourable RFS and overall survival (OS). The induction regimen including both homoharringtonine and intermediate-dose cytarabine was associated with the most favourable RFS (3-year RFS 84.7%) and OS (3-year OS 92.8%) compared to the conventional cytarabine and daunorubicin regimen (3-year RFS 27.7%, hazard ratio [HR] 0.126, 95% confidence interval [CI] 0.051-0.313, Wald p < 0.001; and 3-year OS 56.4%, HR 0.179, 95% CI 0.055-0.586, Wald p = 0.005). In multivariate analyses, the induction regimen including intermediate-dose cytarabine (HR 0.364, 95% CI 0.205-0.646, Wald p < 0.001) and CSF3R mutations (HR 2.667, 95% CI 1.276-5.572, Wald p = 0.009) were independently associated with RFS. Taken together, we found that induction regimen and CSF3R mutations were independent prognostic factors for AML with CEBPAdm.

Comparison of multi-omics results between patients with acute myeloid leukemia with long-term survival and healthy controls.

Background: Acute myeloid leukemia (AML) is a group of highly heterogeneous diseases, for which approximately 35-40% of patients younger than 60 years old can be cured. However, the multi-omics characteristics and immune cell infiltration (ICI) status of adult long-term survival patients with AML patients compared with healthy controls are still relatively under-explored. Methods: A total of 10 healthy transplant donors (control group) and 11 long-term survival patients with AML with de novo sampling from 2019 to 2020 at the Institute of Hematology in the Hospital of Blood Diseases were enrolled. We simultaneously performed 850 K methylation and bulk RNA-seq on these 21 patients for comparing the differential gene methylation and expression levels between the two groups. The analysis of immune cell gene expression was based on 4 algorithms single sample gene set enrichment analysis (ssGSEA), EPIC, ESTIMATE and immunophenotype score (IPS) on the bulk RNA-seq data. Results: The differential methylation positions (DMPs) of the control group was significantly higher than that of the long-term survival group (P<0.01). The hypomethylated probes for Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment is summarized as follows: the significant pathway was related to NK-cell-mediated cytotoxicity and amino acid metabolism. We also found the Differential expression genes (DEGs) of long-term survival AML were roughly similar, and the DEGs were highly relevant to the cellular amino acid metabolic process pathway by gene set enrichment analysis (GSEA). Based on the further univariate and multivariate Cox survival analyses in GSE37642, genes crosslinked of DEGs and DMPs: LOXL1 and PDZRN4, which characterized as hypomethylated and upregulated, may become an AML prognostic marker (P<0.05). Besides, compared with the long-term-survival AML patients who discontinued chemotherapy after >3 years and the healthy donors, T cell-, natural killer cell-, MHC- and effector cell (EC)-related genes were downregulated; suppressor cells (SC) and checkpoint (CP) cells were significantly upregulated in the long-term-survival AML patients who discontinued chemotherapy after <3 years. Conclusions: In terms of DNA methylation, RNA expression and ICI, AML patients with long-term survival were slightly different than that of healthy people. The profile of long-term AML survivors, especially those who discontinued chemotherapy less than 3 years, still differed from that of healthy people.

Efficacy of combination of venetoclax with azacitidine or chemotherapy in refractory/relapse acute leukemias of ambiguous lineage, not otherwise specified.

Acute leukemias of ambiguous lineage, not otherwise specified (ALAL-NOS) is a rare type of acute leukemia. Management of relapse/refractory (R/R) patients is still challenging.traditional chemotherapy treatment is not effective. In this paper, we reported 6 R/R patients diagnosed as ALAL-NOS in our hospital, who were treated with venetoclax based treatment (venetoclax combining with azacitidine or chemotherapy). All 6 patients achieved CR. Five of the six patients received allo-HSCT, four patients were still alive in CR until the follow-up day. Our data provide preliminary evidence and show that venetoclax based regimens are effective and safety in patients with R/R ALAL-NOS.

Gene Deletions and Prognostic Values in B-Linage Acute Lymphoblastic Leukemia.

Although pediatric-like treatment regimen has remarkably improved the survival rates of adults with acute lymphoblastic leukemia (ALL), the outcome of some adult patients is still poor owing to adverse genetic features. These molecular abnormalities, especially gene deletions, may be considered for the prognosis assessment for adult patients with ALL. In this study, using multiplex ligation-dependent probe amplification (MLPA) method, gene deletions were analyzed in from 211 adult B-ALL patients treated in our center. The data showed that 68.2% (144/211) adult B-ALL patients carried gene deletions, and the frequency is much higher in Ph+B-ALL patients. IKZF1 gene deletion is the most common gene deletion in adult B-ALL, followed by CDKN2A/B deletion. In Ph-B-ALL patients, the overall survival of patients with gene deletions is inferior to that of patients without any gene deletions. More obviously, patients with IKZF1 or CDKN2A/B deletion had a worse prognosis, whereas, allogeneic hematopoietic stem cell transplantation could improve OS in patients with IKZF1 deletion, but not in patients with CDKN2A/B deletion. Moreover, the outcome of Ph-B-ALL patients with double deletion of IKZF1and CDKN2A/B may be much worse than that of patients with IKZF1 or CDKN2A/B alone. Minimal residual disease (MRD) was also analyzed together with gene deletions and demonstrated that gene deletions have a negative impact on survival only in MRD positive Ph-B-ALL patients. In conclusion, gene deletions are closely related with the prognosis of adult Ph-B-ALL patients.

Optimized clinical application of minimal residual disease in acute myeloid leukemia with RUNX1-RUNX1T1.

Minimal residual disease (MRD) levels monitored by polymerase chain reaction are associated with outcomes in acute myeloid leukemia with RUNX1-RUNX1T1. The objectives of our study were to quantitatively compare the predictive value of MRD reduction and absolute copies and assess the influence of other prognostic factors on MRD. A total of 224 consecutive patients with RUNX1-RUNX1T1 aged ≤55 years were included in the MRD study. Patients received different induction regimens including conventional- or intermediate-dose cytarabine plus low-dose daunorubicin and omacetaxine mepesuccinate or daunorubicin at 60 mg/m2/day on days 1-3. As continuous variables, both MRD reduction and absolute MRD level were significantly associated with cumulative incidence of relapse (CIR; hazard ratio [HR] = 1.610, 95% confidence interval [CI]: 1.370-1.890, p < 0.001, and HR = 1.170, 95% CI: 1.120-1.230, p < 0.001, respectively). For the CIR, the area under the curves (AUCs) of MRD reduction and absolute MRD level after the first consolidation chemotherapy were 0.629 and 0.629, respectively. Intermediate-dose cytarabine induction (HR = 0.494; p = 0.039 for CIR, HR, 0.451; p = 0.014 for RFS, and HR, 0.262; p = 0.006 for OS) remained significantly associated with outcomes after adjusting for MRD reduction after the first consolidation therapy (HR = 1.456, p < 0.001, for CIR; HR = 1.467, p = 0.001, for relapse-free survival; and HR = 1.468, p = 0.014, for overall survival) in multivariate analyses. In conclusion, the prognostic significance of MRD after the first consolidation therapy was influenced by the induction regimen in acute myeloid leukemia with RUNX1-RUNX1T1.

Prognostic significance of copy number alterations detected by multi-link probe amplification of multiple genes in adult acute lymphoblastic leukemia.

The multiplex ligation-dependent probe amplification (MLPA) method was used to detect the copy number alterations (CNAs) of IKAROS family zinc finger 1 (IKZF1), paired box 5 (PAX5), ETS variant 6 (ETV6), RB transcriptional corepressor 1 (RB1), BTG anti-proliferation factor 1 (BTG1), early B-cell factor 1 (EBF1), cyclin dependent kinase inhibitor 2A/2B (CDKN2A/2B) and cytokine receptor like factor 2 (CRLF2) genes in 87 adults with acute lymphoblastic leukemia (ALL) in China. The effects of CNAs on prognosis were analyzed. Gene deletions were detected in 58/87 (66.7%) ALL patients. The most common deletions were observed in the following genes: IKZF1 (40.6%), CDKN2A (31.9%), CDKN2B (29%), PAX5 (21.7%), RB1 (14.5%) and BTG1 (10.1%). B cell-ALL (B-ALL) patients with CDKN2A/2B deletions exhibited poor 2-year overall survival (OS; P=0.055) and relapse-free survival (RFS; P=0.054) rates. CDKN2A/2B deletions were associated with poor 2-year OS (P=0.045) and RFS (P=0.071) rates in Philadelphia chromosome positive (Ph+) B-ALL patients, as well as in the high risk (HR) B-ALL group (P=0.037 and P=0.047, respectively). Patients with PAX5 deletions displayed poor 2-year OS (P=0.004) and RFS (P=0.016) rates in Philadelphia chromosome negative (Ph-) B-ALL patients. Patients with ≥3 gene deletions exhibited a poorer prognosis than other patients (OS, P=0.001; RFS, 0.002).

Spectrum of somatic mutations detected by targeted next-generation sequencing and their prognostic significance in adult patients with acute lymphoblastic leukemia.

Target-specific next-generation sequencing technology was used to analyze 112 genes in adult patients with acute lymphoblastic leukemia (ALL). This sequencing mainly focused on the specific mutational hotspots. Among the 121 patients, 93 patients were B-ALL (76.9%), and 28 patients (23.1%) were T-ALL. Of the 121 patients, 110 (90.9%) harbored at least one mutation. The five most frequently mutated genes in T-ALL are NOTCH1, JAK3, FBXW7, FAT1, and NRAS. In B-ALL, FAT1, SF1, CRLF2, TET2, and PTPN1 have higher incidence of mutations. Gene mutations are different between Ph+ALL and Ph-ALL patients. B-ALL patients with PTPN11 mutation and T-ALL patients with NOTCH1 and/or FBXW7 mutations showed better survival. But B-ALL with JAK1/JAK2 mutations showed worse survival. The results suggest that gene mutations exist in adult ALL patients universally, they are related with prognosis.

IKZF1 alterations and expression of CRLF2 predict prognosis in adult Chinese patients with B-cell precursor acute lymphoblastic leukemia.

Acute Lymphoblastic Leukemia (ALL) is a common hematological malignancy in children, with a prognosis much worse in adults. The molecular characterization of ALL and its correlated prognostic significance are largely unknown. In this study, we analyzed the frequency of IKZF1 deletions, IK6 isoform, and CRLF2 overexpression in 118 Chinese adult B-cell precursor ALL (B-ALL) patients to explore their associations with clinical prognosis. Our data showed that IKZF1 deletions and IK6 isoform were highly detected in adult patients, and both of them were related with worse prognosis in Ph- B-ALL, HR group of Ph- B-ALL, and/or B-ALL patients. Though the frequency of CRLF2 overexpression was similar to children, it had an independent prognostic significance for standard-risk and Ph- adult patients. Our study provided insights into the prognostic significance of certain genetic features in B-ALL patients. Further therapeutic strategies targeting these abnormalities potentially improving the prognosis of B-ALL are warranted.

Role of Retinal Nerve Fiber Layer Thickness and Optic Disk Measurement by OCT on Early Diagnosis of Glaucoma.

PURPOSE: Glaucoma is an eye disease that can lead to irreversible optic nerve damage and cause blindness. Optical coherence tomography (OCT) allows an early diagnosis of glaucoma by the measurements of the retinal nerve fiber and optic disc parameters. A retrospective study was designed to analyze the effects of the measurement of the retinal nerve fiber layer (RNFL) thickness and the optic disc tomography by spectral-domain OCT on the early diagnosis of suspected glaucoma and primary open angle glaucoma (POAG). METHODS: This was a clinical case-control study. The RNFL thickness around the optic disc and optic disk tomographic parameters of the control (n = 51, 98 eyes), suspected glaucoma (n = 81, 146 eyes), and POAG groups (n = 55, 106 eyes) were measured by OCT. The parameters included superior, inferior, nasal and temporal mean RNFL thickness, disc area (DA), cup area (CA), rim area (RA), disc volume (DV), cup volume (CV), rim volume (RV), cup/disc area ratio (CA/DA), rim/disc area ratio (RA/DA), cup/disc volume ratio (CV/DV) and rim/disc volume ratio (RV/DV). RESULTS: Superior, nasal, and mean RNFL parameters, DA, CA,RA, DV, CV, CA/DA, RA/DA, CV/DV and RV/DV significantly differed among three groups by single-factorial ANOVA. Inferior and temporal RNFL thickness significantly differed between the control and POAG groups. No significant difference was observed in RV among three groups. In the POAG group, the maximum area under the ROC curve (AROC) of mean RNFL thickness was 0.845. The maximum AROC of optic disk parameters was RA/DA (0.998), followed by CA/DA (0.997). The AROC of CA, RA, CV, and DV were all > 0.900. CONCLUSION: OCT may serve as a useful diagnostic modality in distinguishing suspected glaucoma from POAG.

[Study on microsurgical procedures for pterygium operation and its therapeutic effects].

OBJECTIVE: To study the microsurgical procedures for the treatment of large primary pterygium and their therapeutic effects. To observe the recurrence rate, the changes of visual acuity after microsurgery and the pathological relationships between pterygium and cornea/sclera under the surgical microscope. METHODS: Forty-six eyes of forty-one patients with pterygium which invading the cornea over the pupil border were included. Pterygium was dissected by various methods under surgical microscope. The pathological relationship between the pterygium and cornea/sclera was observed. The lengths of the pterygium head and its three parts were measured. Degenerative Tenon's capsule was removed totally and the wound was covered by rotated conjunctival flaps. These patients were followed-up for 12.0 - 50.2 months (median: 22.4 months). Changes in visual acuity and recurrence rate after operation were observed. RESULTS: The average length of the total pterygium heads was (6.3 +/- 0.4) mm. The head was divided into three parts: the apical, loose and adhesive parts. The apical part was located at the top of the pterygium head with a length of (1.7 +/- 0.4) mm. The tissue of apical part was compact, hard, translucent and adhered to the cornea tissue. The adhesive part was a band in front of the anterior border of the limbus and paralleled to the limbus. The width of adhesive part was (0.9 +/- 0.1) mm and was tightly adhered to the cornea. The loose part lied between the apical and the adhesive part. The length of which was (3.6 +/- 0.4) mm and could be separated from the cornea easily. The neck and the body parts of pterygium could be separated easily from the limbus and sclera. Non-corrected visual acuity averaged 0.3 (ranged from finger count to 0.7) before the operation and averaged 0.7 (ranged from finger count to 1.5) 1 month postoperatively (Wilcoxon signed rank test u = 5.435, P < 0.01). Pterygium relapsed in 5 eyes with a recurrence rate of 11% (5/46). CONCLUSIONS: There is a regular pathological relationship between the pterygium and the cornea/sclera under surgical microscope, which is fundamental for the microsurgery of the pterygium. Extensively degenerated Tenon's capsule should be removed totally and the defect should be covered by rotated conjunctival flaps. The recurrence rate is low and the visual acuity increases significantly after the operation.