Objective:To investigate a new method for rapid detection of the MYOD1 L122R mutation and to analyze the clinical and pathological characteristics of mutation-positive rhabdomyosarcoma.Methods:A MYOD1 mutation detection kit was developed using allele-specific Taqman fluorescence probe technology. A total of 80 rhabdomyosarcoma samples diagnosed at Beijing Children′s Hospital, Capital Medical University from June 2022 to June 2023 were collected for testing. The detection sensitivity, specificity, and consistency rate of the kit were compared with those of the gold standard Sanger sequencing. The demographic, histopathological, and molecular genetic characteristics of patients with MYOD1 mutations were analyzed.Results:Among the 80 rhabdomyosarcoma cases, there were 46 males and 34 females, with an age of onset ranging from 0 to 16 years [mean (6.0±4.4) years], including 32 embryonal rhabdomyosarcoma, 18 alveolar rhabdomyosarcoma, and 30 spindle cell/sclerosing rhabdomyosarcoma. The new kit screened a total of 11 mutations, of which 10 were spindle cell/sclerosing rhabdomyosarcoma and one was embryonal rhabdomyosarcoma. Patients with MYOD1 mutations were typically older (four cases over 10 years old) but could also occur in young children (the youngest being 3-year and 2-month-old). The primary sites were the head and neck region in eight cases, limbs in two cases, and pelvic cavity in one case. Among the six patients with available staging information at initial diagnosis, one was classified as stage 2 and five were stage 3, all of which were intermediate risk. Among the 11 mutation patients, six had recurrence and metastasis, with three deaths; the remaining patients had not shown tumor progression until last follow-up. Compared with the wild type group, the expression level of MYOD1 in mutation patients increased significantly ( χ2=10.66, P=0.01), while the event-free survival rate ( χ2=9.925, P<0.01) and overall survival ( χ2=4.53, P=0.03) rate decreased. Compared with Sanger sequencing, the kit achieved 100% sensitivity and specificity. The kit had a minimum mutation content detection limit of 2% and the reaction could be finished within 2 hours. Additionally, this kit might also be used to detect the expression of MYOD1, thereby aiding the diagnosis of rhabdomyosarcoma. Conclusions:The study has established a new method for accurate and rapid detection of MYOD1 mutation in rhabdomyosarcoma, particularly suitable for the formalin-fixed and paraffin-embedded samples in clinical settings. MYOD1 mutations more likely occur in spindle cell/sclerosing rhabdomyosarcoma of the head and neck region in children. Patients with MYOD1 mutations have an extremely poor prognosis, which is independent of clinical staging and grading. MYOD1 mutation detection in rhabdomyosarcoma has significant value for auxiliary diagnosis and prognostic assessment.

Objective:To investigate a new method for rapid detection of the MYOD1 L122R mutation and to analyze the clinical and pathological characteristics of mutation-positive rhabdomyosarcoma.Methods:A MYOD1 mutation detection kit was developed using allele-specific Taqman fluorescence probe technology. A total of 80 rhabdomyosarcoma samples diagnosed at Beijing Children′s Hospital, Capital Medical University from June 2022 to June 2023 were collected for testing. The detection sensitivity, specificity, and consistency rate of the kit were compared with those of the gold standard Sanger sequencing. The demographic, histopathological, and molecular genetic characteristics of patients with MYOD1 mutations were analyzed.Results:Among the 80 rhabdomyosarcoma cases, there were 46 males and 34 females, with an age of onset ranging from 0 to 16 years [mean (6.0±4.4) years], including 32 embryonal rhabdomyosarcoma, 18 alveolar rhabdomyosarcoma, and 30 spindle cell/sclerosing rhabdomyosarcoma. The new kit screened a total of 11 mutations, of which 10 were spindle cell/sclerosing rhabdomyosarcoma and one was embryonal rhabdomyosarcoma. Patients with MYOD1 mutations were typically older (four cases over 10 years old) but could also occur in young children (the youngest being 3-year and 2-month-old). The primary sites were the head and neck region in eight cases, limbs in two cases, and pelvic cavity in one case. Among the six patients with available staging information at initial diagnosis, one was classified as stage 2 and five were stage 3, all of which were intermediate risk. Among the 11 mutation patients, six had recurrence and metastasis, with three deaths; the remaining patients had not shown tumor progression until last follow-up. Compared with the wild type group, the expression level of MYOD1 in mutation patients increased significantly ( χ2=10.66, P=0.01), while the event-free survival rate ( χ2=9.925, P<0.01) and overall survival ( χ2=4.53, P=0.03) rate decreased. Compared with Sanger sequencing, the kit achieved 100% sensitivity and specificity. The kit had a minimum mutation content detection limit of 2% and the reaction could be finished within 2 hours. Additionally, this kit might also be used to detect the expression of MYOD1, thereby aiding the diagnosis of rhabdomyosarcoma. Conclusions:The study has established a new method for accurate and rapid detection of MYOD1 mutation in rhabdomyosarcoma, particularly suitable for the formalin-fixed and paraffin-embedded samples in clinical settings. MYOD1 mutations more likely occur in spindle cell/sclerosing rhabdomyosarcoma of the head and neck region in children. Patients with MYOD1 mutations have an extremely poor prognosis, which is independent of clinical staging and grading. MYOD1 mutation detection in rhabdomyosarcoma has significant value for auxiliary diagnosis and prognostic assessment.

Purpose To study the clinical and pathological features of angiomatoid fibrous histocytoma(AFH)and to ex-plore its diagnosis,differential diagnosis and prognosis.Meth-ods The clinicopathological and follow-up data were analyzed in 14 cases of AFH,and the literatures were reviewed.Results There were 11 males and 3 females.The age ranged from 11 months to 12 years and 11 months,with average 5.9 years.3 cases were located in limbs,and 5 cases in trunk,5 cases in head and neck region,and 1 of intracranial tumor.Histological-ly,14 cases were composed of fibrous capsules and lymphocyte sheaths,and cell nucleus were vacuolar,forming fascicles with focal whirling and synteny.Intralesional pseudoangiomatous spaces were noted in 9 cases.Calcification was found in 2 ca-ses.2 cases showed high mitotic acticity(11/10 HPF).Scle-rosing and/or myxoid stroma was seen in 3 cases.Tumors were immunopositive for desmin(10/14),EMA(12/14),CD99(12/14),SMA(9/12),ALK(7/8),and the average of Ki67 index was 16％.7 cases harbored EWSR1 rearrangenent(part-ner gene not identified),2 cases had EWSR1-ATF1 fusion and 2 EWSR1-CREB1 fusion.Clinical follow-up information was a-vailable for 14 cases(average 46 months).All the 14 cases were alive without recurrence and metastasis.Conclusion AFH is a borderline or low-grade malignant tumor,often demon-strates indolent behavior in children,but rarely recurs and me-tastasizes.The diagnosis and differential diagnosis require a comprehensive analysis of clinical features,histopathologic changes,immunohistochemical finding and EWSR1 or FUS gene detection results.

Objective:To investigate the relationship between 1p/16q loss of heterozygosity (LOH) and 1p gain in Wilms tumor and their clinicopathologic characteristics and prognosis.Methods:A total of 175 Wilms tumor samples received from the Department of Pathology, Beijing Children′s Hospital from September 2019 to August 2022 were retrospectively analyzed. The histopathologic type and presence of lymph node involvement were evaluated by two pathologists. The clinical data including patients′gender, age, tumor location, preoperative chemotherapy, and tumor stage were summarized. Fluorescence in situ hybridization (FISH) was done to detect 1p/16q LOH and 1p gain and their correlation with the clinicopathological features and prognosis were analyzed.Results:Among the 175 samples, 86 cases (49.1%) were male and 89 (50.9%) were female. The mean age was (3.5±2.9) years, and the median age was 2.6 years. There were 26 (14.9%) cases with 1p LOH, 28 (16.0%) cases with 16q LOH, 10 (5.7%) cases of LOH at both 1p and 16q, and 53 (30.3%) cases with 1q gain. 1q gain was significantly associated with 1p LOH ( P<0.01) and 16q LOH ( P<0.01). There were significant differences ( P<0.01) between 1q gain, 1p LOH and 16q LOH among different age groups. The rate of 16q LOH in the high-risk histopathological subtype (50.0%) was significantly higher than that in the intermediate-risk subtype (13.6%, P<0.05). The frequency of 1q gain, 1p LOH, and 16q LOH in children with advanced clinical stages (Ⅲ and Ⅳ) was significantly higher than that in children with early clinical stages (Ⅰ and Ⅱ). 1q gain, 1p LOH, and 16q LOH showed no significant correlation with gender, unilateral or bilateral disease, chemotherapy, or lymph node metastasis. The progression-free survival (PFS) time for patients with 1q gain and 1p LOH was significantly shorter than those without these aberrations ( P<0.05). Additionally, the PFS time of patients with 16q LOH was slightly shorter than those with normal 16q, although the difference was not statistically significant. Patients with stage Ⅲ to Ⅳ disease exhibiting 1q gain or 1p LOH had a significantly higher relative risk of recurrence, metastasis, and mortality. Conclusions:1p/16q LOH and 1q gain are associated with age, high-risk histological type, and clinical stage in Wilms tumor. 1q gain and 1p LOH are significantly correlated with the prognosis of Wilms tumor.

Objective:To investigate the clinicopathological features, immunophenotype and molecular genetic characteristics of congenital spindle cell/sclerosing rhabdomyosarcoma.Methods:Sixteen cases (including 10 consultation cases) of congenital spindle cell/sclerosing rhabdomyosarcoma diagnosed at the Beijing Children′s Hospital, Capital Medical University, Beijing China, from April 2017 to January 2022 were collected. These cases were evaluated for clinical profiles, histomorphological features, immunophenotype and molecular characteristics.Results:Among the 16 patients, 9 were male and 7 were female. Five cases were present during maternal pregnancy and 11 cases were found immediately after birth. The tumors were located in the chest wall, low back, retroperitoneum, extremities or perineum. The tumors consisted of fasciculated spindle-shaped cells with localized mesenchymal sclerosis and vitreous metaplasia. Immunohistochemistry showed that the tumor cells expressed Desmin, Myogenin, MyoD1, SMA, CD56 and ALK to varying degrees, but not other markers such as CD34, CD99, pan-TRK, S-100 and BCOR. FISH analyses with NCOA2 (8q13) and VGLL2 (6q22) gene breakage probes revealed a breakage translocation in chromosome NCOA2 (8q13) in 4 cases (4/11). In the 6 cases subject to sequencing, a mutation at the p.L122R locus of MYOD1 gene was detected in 1 case (1/6). Two cases were examined by electron microscopy, which showed bundle-arranged myofilaments with some primitive myofilament formation. Five cases were resected with simple surgery, 2 cases were biopsied and followed up with observation only, and 9 cases were treated with surgery and adjuvant chemotherapy. Follow-up was available in 12 cases. At the end of the follow-up, 2 of the 12 patients developed local recurrences and 2 patients survived with disease.Conclusions:Congenital spindle cell/sclerosing rhabdomyosarcoma is a rare subtype of congenital rhabdomyosarcoma. It more commonly occurs in the chest, back and lower limbs of infants than other sites. NCOA2/VGLL2 gene fusion seems to be the most common genetic change. Its prognosis is better than other subtypes of rhabdomyosarcoma and those in adolescents and adults with the same subtype. Analysis and summary of its clinicopathological features can help differentiate it from other soft tissue tumors in infants and children and provide the information for appropriate treatments.

AIM:To establish a mouse model of pulmonary fibrosis induced by multiple intratracheal instilla-tions of bleomycin(BLM).METHODS:C57BL/6J mice were randomly divided into five groups:control group(n=5),multiple high-dose BLM(BLM-MH)group(n=10),multiple medium-dose BLM(BLM-MM)group(n=8),multiple low-dose BLM(BLM-ML)group(n=7),and single medium-dose BLM(BLM-SM)group(n=6).The pulmonary fibrosis mod-el was induced by single or multiple intratracheal instillations of BLM.Survival curves were plotted at day 56,and lung tis-sue was collected for lung coefficient calculation.Pathological changes in lung tissue were assessed using hematoxylin-eo-sin(H&E)staining and Masson staining.Indicators of lung fibrosis,such as hydroxyproline(HYP),were measured.Dif-ferentially expressed genes in patients with IPF were screened using the GEO database,and kyoto encyclopedia of genes and genomes(KEGG)pathway enrichment analysis was performed to identify pathways associated with IPF.Western blot was used to detect changes in these pathways in the lung tissues of the model mice.RESULTS:The survival rates were 50%in the BLM-MH group and 87.5%in the BLM-MM group,with no deaths in other groups.Compared with the control group,the BLM-MH and BLM-MM groups showed significantly increased lung coefficients(P＜0.05),lung tissue dam-age,inflammation levels,degree of pulmonary fibrosis(P＜0.05 or P＜0.01),and HYP content.The BLM-MH and BLM-MM groups,compared with the BLM-SM group,showed significantly elevated levels of inflammation,fibrosis,and HYP content(P＜0.05 or P＜0.01).GEO database and KEGG enrichment analysis revealed that the extracellular matrix-recep-tor interaction pathway(ECM-RIP)may be involved in IPF development.The expression levels of ECM-RIP pathway-re-lated proteins,such as phosphorylated focal adhesion kinase(p-FAK)and phosphorylated Src protein(p-Src),were in-creased in the lung tissues of the model mice compared with the control group.Compared with the BLM-SM group,the BLM-MH group exhibited significant increases in the protein levels of p-FAK and p-Src in the lung tissue(P＜0.05).CONCLUSION:The murine model of pulmonary fibrosis established through repeated intratracheal instillations of BLM effectively mimics the pathological characteristics of the disease,providing a valuable experimental model for the investiga-tion of idiopathic pulmonary fibrosis pathogenesis and for the development of therapeutic agents.

AIM:To establish a mouse model of pulmonary fibrosis induced by multiple intratracheal instilla-tions of bleomycin(BLM).METHODS:C57BL/6J mice were randomly divided into five groups:control group(n=5),multiple high-dose BLM(BLM-MH)group(n=10),multiple medium-dose BLM(BLM-MM)group(n=8),multiple low-dose BLM(BLM-ML)group(n=7),and single medium-dose BLM(BLM-SM)group(n=6).The pulmonary fibrosis mod-el was induced by single or multiple intratracheal instillations of BLM.Survival curves were plotted at day 56,and lung tis-sue was collected for lung coefficient calculation.Pathological changes in lung tissue were assessed using hematoxylin-eo-sin(H&E)staining and Masson staining.Indicators of lung fibrosis,such as hydroxyproline(HYP),were measured.Dif-ferentially expressed genes in patients with IPF were screened using the GEO database,and kyoto encyclopedia of genes and genomes(KEGG)pathway enrichment analysis was performed to identify pathways associated with IPF.Western blot was used to detect changes in these pathways in the lung tissues of the model mice.RESULTS:The survival rates were 50%in the BLM-MH group and 87.5%in the BLM-MM group,with no deaths in other groups.Compared with the control group,the BLM-MH and BLM-MM groups showed significantly increased lung coefficients(P＜0.05),lung tissue dam-age,inflammation levels,degree of pulmonary fibrosis(P＜0.05 or P＜0.01),and HYP content.The BLM-MH and BLM-MM groups,compared with the BLM-SM group,showed significantly elevated levels of inflammation,fibrosis,and HYP content(P＜0.05 or P＜0.01).GEO database and KEGG enrichment analysis revealed that the extracellular matrix-recep-tor interaction pathway(ECM-RIP)may be involved in IPF development.The expression levels of ECM-RIP pathway-re-lated proteins,such as phosphorylated focal adhesion kinase(p-FAK)and phosphorylated Src protein(p-Src),were in-creased in the lung tissues of the model mice compared with the control group.Compared with the BLM-SM group,the BLM-MH group exhibited significant increases in the protein levels of p-FAK and p-Src in the lung tissue(P＜0.05).CONCLUSION:The murine model of pulmonary fibrosis established through repeated intratracheal instillations of BLM effectively mimics the pathological characteristics of the disease,providing a valuable experimental model for the investiga-tion of idiopathic pulmonary fibrosis pathogenesis and for the development of therapeutic agents.

OBJECTIVE: To explore the effect of vinyl chloride on the blood sex hormones and liver function of male workers. METHODS: A total of 129 male vinyl chloride workers(exposure group) and 128 male office workers who were not exposed to occupational hazards(control group) were selected as study subjects by judgment sampling method. The time weighted average concentration(C_(TWA)) of vinyl chloride in the workplace air was measured. The level of urine thiodiglycolic acid(TDGA), blood routine, electrocardiogram and liver B-ultrasound were performed on the subjects. The serum levels of liver function and sex hormones were measured. RESULTS: The median of C_(TWA) of vinyl chloride in the workplace was 0.90 mg/m~3, and the geometric mean was 1.40 mg/m~3. The level of urine TDGA in the exposed group was higher than that of the control group(median: 0.68 vs 0.02 mg/g Cr, P<0.01). The abnormal rate of hemoglobin level, erythrocyte count, leukocyte count, hematocrit, mean platelet volume, aspartate transaminase, total bilirubin, indirect bilirubin and liver B-ultrasound increased in the exposure group than that of the control group(P<0.05). The levels of serum prolactin, leuteinizing hormone(LH), follicle-stimulating hormone and estradiol in the exposure group increased, the abnormal rates of prolactin, LH and estradiol increased, and the level of testosterone decreased compared with the control group(P<0.05). The levels of prolactin in the low-, medium-and high-TDGA subgroups in the exposure group increased(P<0.05), and the abnormal rates increased compared with the control group(P<0.017). CONCLUSION: Vinyl chloride can cause liver function damage in male workers and have reproductive toxicity. Prolactin can be used as a biomarker of reproductive toxicity of vinyl chloride.

Objective To explore the clinical significance and gene mutation profiles of renal transplant patients with unconjugated hyperbilirubinemia (Gilbert's syndrome).Methods Genomic DNA was extracted from peripheral blood samples of 8 renal transplant patients with Gilbert'S syndrome.UGT1A1 * 6 and UGT1A1 * 28 genotypes were identified through digital fluorescence molecular hybridization and DNA sequencing.Results There are 2 cases of UGT1A1 * 28 heterozygous mutant,3 cases of UGT1A1 * 6 homozygous mutant,2 case of UGT1A1 * 6 heterozygous mutant,1 case of UGT1A1 * 28 heterozygous mutant combined with UGT1A1 * 6 heterozygous mutant.Conclusion There is a higher heterozygous or homozygous gene mutation rate of UGT1A1 * 6 and UGT1A1 * 28 in renal transplant patients with Gilbert's syndrome.Genetic mutation of UGT1A1 * 6 and UGT1A1 * 28 may be the reason of Gilbert's syndrome after renal transplant.