[Multiple primary tumors in children: a clinicopathological analysis of four cases].

Objective: To investigate the clinicopathological features of children with metachronous or synchronous primary tumors and to identify related genetic tumor syndromes. Methods: The clinicopathological data of 4 children with multiple primary tumors diagnosed in the Xinhua Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China from 2011 to 2023 were collected. The histological, immunophenotypic and molecular characteristics were examined using H&E staining, immunohistochemical staining, PCR, Sanger sequencing and next-generation sequencing (NGS). The patients were followed up. Results: Case 1 was an 8-year-old boy with the adrenal cortical carcinoma, and 5 years later a poorly differentiated gastric adenocarcinoma was detected. Case 2 was a 2-year-old boy, presented with a left ventricular choroid plexus carcinoma, and a hepatoblastoma was detected 8 months later. Case 3 was a 9-month-old girl, diagnosed with renal rhabdoid tumor first and intracranial atypical teratoid/rhabdoid tumor (AT/RT) 3 months later. Case 4 was a 7-year-old boy and had a sigmoid colon adenocarcinoma 3 years after the diagnosis of a glioblastoma. The morphology and immunohistochemical features of the metachronous or synchronous primary tumors in the 4 cases were similar to the corresponding symptom-presenting/first-diagnosed tumors. No characteristic germ line mutations were detected in cases 1 and 2 by relevant molecular detection, and the rhabdoid tumor predisposition syndrome was confirmed in case 3 using NGS. Case 4 was clearly related to constitutional mismatch repair deficiency as shown by the molecular testing and clinical features. Conclusions: Childhood multiple primary tumors are a rare disease with histological morphology and immunophenotype similar to the symptom-presenting tumors. They are either sporadic or associated with a genetic (tumor) syndrome. The development of both tumors can occur simultaneously (synchronously) or at different times (metachronously). Early identification of the children associated with genetic tumor syndromes can facilitate routine tumor screening and early treatment.

[Adrenal cortical carcinoma in children: a clinicopathological analysis of 25 cases].

Objective: To investigate the clinicopathological features, diagnosis and differential diagnosis of adrenal cortical carcinoma (ACC) in children. Methods: Twenty-five children with ACC diagnosed in the Department of Pathology, Xinhua Hospital Affiliated to Shanghai Jiaotong University School of Medicine, Shanghai, China from March 2014 to August 2022 were retrospectively analyzed. The related literature was reviewed. Results: A total of 25 children with ACC were collected, including 11 males and 14 females, with a male to female ratio of 1.0∶1.3. The patient ages ranged from 8 months to 14 years (median, 4 years). Eighteen cases with clinical data had functional tumors (18/22, 81.8%) presenting with virilization or precocious puberty (15/18), symptoms related to hypercortisolism (8/18) or endocrine symptoms mixed with both (5/18), while 3 cases (3/22, 13.6%) had unknown clinical data. The clinical manifestations of four patients with nonfunctional tumors were an abdominal mass and/or abdominal pain, walking instability and others. Grossly, the average maximum diameter of the tumor was 9.4 cm. Most of the tumors were nodular and partially encapsuled. The cut surfaces were gray or gray brown, soft with hemorrhage. Histologically, the tumor cells were diffusely distributed, separated by a vascular-rich network. The tumor cells were large, with distinct nucleoli, abundant eosinophilic or clear cytoplasm, and round or oval nuclei. The mitotic index was high, and atypical mitoses were common. Necrosis, calcification, capsule invasion or/and venous invasion were present. In some cases, the tumor invaded the surrounding soft tissues or kidneys. Immunohistochemically, the tumor cells were diffusely positive for syn and SF1 and focally positive for α-inhibin, Melan A and Calretinin, but negative for CgA. Ki-67 proliferation index ranged from 2%-90%. TP53 gene status was examined in 7 cases, in which mutations were detected in 4 cases. Follow-up data was obtained in 21 patients, among whom 18 received chemotherapy and 3 received radiotherapy. Distant metastasis occurred in 13 patients. Median progression-free survival (PFS) was 11.2 months and median overall survival (OS) was 54.7 months. Patients aged less than 5 years had a better prognosis for OS (P<0.05) than the older ones (≥5 years), but a similar PFS (P>0.05). Male patients and Ki-67 proliferation index <15% had a better prognosis tendency for OS, but there was no statistically significant difference (P>0.05). Conclusions: ACC in children is a rare, often functional tumor associated with Li-Fraumeni genetic syndrome and has a poor prognosis. Diagnosis and differential diagnosis require a combination of morphological, phenotypic and clinical analysis.

A prospective multicentre controlled study of Gaoweikang (Chinese multiherb extract-based tincture) used in high-risk HPV infections.

OBJECTIVE: The aim of the study was to investigate the safety and antiviral efficacy of a Chinese multiherb extract-based tincture (GWK) on a population of patients with high-risk human papilloma (hrHPV) infections and hrHPV-caused cervical low-grade squamous intraepithelial lesions (LSILs). PATIENTS AND METHODS: Patients with persistent hrHPV infection were enrolled in Group A, including A1 subjects, who received the intervention, and A2 subjects, who received the control. Patients with hrHPV infection causing cervical LSIL were enrolled in Group B, which included B1 subjects, who received the intervention, and B2 subjects, who served as the control. For Groups A1 and B1, hrHPV was tested at 3 months (M3) and 6 months (M6) after the intervention. The side effects were also analyzed. RESULTS: At baseline (D0), a total of 99 patients were enrolled in Group A, with 50 subjects in Group A1 and 49 subjects in Group A2. A total of 91 patients were enrolled in Group B, with 45 subjects in Group B1 and 46 subjects in Group B2. There was no significant difference in the characteristics, including average age, age stratification, and HPV genotype. At M6, both Group A1 and Group B1 had a higher hrHPV clearance rate than the control group (A1/A2: 80.0% vs. 20.4%; B1/B2: 64.4% vs. 15.2%, p<0.001). At M6, the effective rates of Group A1 and Group B1 were 84% (42/50) and 68.9% (31/45), respectively. The side effect rates of Groups A1 and B1 were 11.5% (6/52) and 11.1% (5/45), respectively. Most adverse reactions involved local discomfort, including vulvar erythema, vulvar itch, increased vaginal discharge, cervical bleeding, and mild pain in the lower abdomen. Univariate logistic regression analysis showed that the intervention had an OR of 12 (95% CI 4.431-32.50) for clearing persistent HPV infection (p<0.001). For cervical LSIL, the intervention had an OR of 10.1 for clearing persistent HPV infection (95% CI 3.68-27.7) (p<0.001). CONCLUSIONS: The results of this study suggest that the Chinese multiherb extract-based tincture GWK is safe and well tolerated. Furthermore, this preliminary study showed that this Chinese multiherb extract-based tincture is helpful for promoting HPV clearance in cases of persistent HPV and HPV-induced LSIL.

[Primary adrenal NK/T cell lymphoma: a clinicopathologic analysis of six cases].

Objective: To investigate the clinicopathologic features of primary adrenal NK/T cell lymphoma (PANKL). Methods: Six cases of PANKL were collected at Henan Provincial People's Hospital from January 2000 to December 2021. The clinicopathologic features including morphology, immunophenotype, treatment and prognosis were retrospectively analyzed, and relevant literature was reviewed. Results: There were two males and four females. The median age was 63 years (ranged from 57 to 68 years). The tumors involved bilateral adrenal glands in 4 cases and unilateral adrenal gland in 2 cases. The main clinical symptom was low back pain without obvious cause. Serum lactate dehydrogenase (LDH) is elevated in five cases. The imaging feature was rapidly enlarging mass initially confined to unilateral/bilateral adrenal glands. Morphologically, the lymphoid cells were mainly medium-sized with a diffuse growth pattern. Coagulative necrosis and nuclear fragmentation were common. Angioinvasion was seen. Immunophenotypically, the neoplastic cells were positive for CD3, CD56 and TIA-1 while CD5 was negative in 5 cases. All cases were positive for EBER by in situ hybridization with more than 80% proliferative activity by Ki-67. Four cases received chemotherapy, one case underwent surgery, and one case underwent surgery with chemotherapy. Follow-up was done in 5 cases; one case was lost to follow-up. Three patients died with a median survival of 11.6 months (3-42 months). Conclusions: PANKL is rare with highly aggressive clinical presentation and poor prognosis. Accurate diagnosis entails correlation of histomorphology, immunohistochemistry, EBER in situ hybridization and clinical history.

[Efficacy and safety of neoadjuvant chemotherapy combined with PD-1 antibody for esophageal squamous cell carcinoma in the real world].

Objective: To evaluate the efficacy and safety of neoadjuvant chemotherapy combined with programmed death-1 (PD-1) antibody in operable, borderline or potentially resectable locally advanced esophageal squamous cell carcinoma(ESCC) in the real world. Methods: The study retrospectively analyzed 28 patients with operable or potentially resectable locally advanced ESCC patients treated with preoperative chemotherapy combined with PD-1 inhibitor in Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School from April 2020 to March 2021. According to the clinical TNM staging system of the 8th edition of the American Joint Committee on Cancer, there were 1, 15, 10, 1 and 1 case of stage Ⅱ, Ⅲ, ⅣA, ⅣB and unknown stage respectively. The treatment was two cycle of dual drug chemotherapy regimen including taxane plus platinum or fluorouracil combined with PD-1 antibody followed by tumor response assessment and surgery if the patient was eligible for resection. Results: Of the 28 patients, 1, 2, 3 and 4 cycles of chemotherapy combined with PD-1 antibody treatment completed in 1, 21, 5, and 1 patient, respectively. Objective response rate (ORR) was 71.4% (20/28), and disease control rate (DCR) was 100% (28/28). The incidence of adverse events exceeding grade 3 levels was 21.4% (6/28), including 3 neutropenia, 1 leukopenia, 1 thrombocytopenia and 1 immune hepatitis. There was no treatment-related death. Of the 23 patients underwent surgery, R0 resection rate was 87.0% (20/23), 13 patients had down staged to the T1-2N0M0 I stage, the pCR rate was 17.3% (4/23), and the pCR rate of primary tumor was 21.7% (5/23). Four patients received definitive chemoradiotherapy. One patient rejected surgery and other treatment after achieved PR response. Conclusion: Neoadjuvant chemotherapy combined PD-1 inhibitor is safe and has high efficacy in operable, borderline or potentially resectable locally advanced ESCC, and it is a promising regimen.

[A preliminary study on the establishment of trachea respiratory passage invaded by thyroid malignant tumor].

Objective: To investigate the establishment of trachea respiratory passage invided by advanced thyroid malignant tumor. Methods: Review of 14 cases with the establishment of trachea respiratory passage invided by advanced thyroid cancer was conducted who were treated at the Department of Otorhinolaryngology Head and Neck Surgery, Zhongda Hospital Southeast University between 2016 and 2020. There were 5 males and 9 females, aged from 24-79 years old. Shin grade was as follows，5 cases with Ⅱ grade, 6 with Ⅲ grade, and 3 with Ⅳ grade. Based on the conditions of tracheal compression and tumor extent, three types of managements were used: patients with the narrowest tracheal diameter>5 mm (8 cases with dyspnea Ⅰ-Ⅱ, Shin grade Ⅱ-Ⅲ) were applied with local surface anesthesia and conscious endotracheal intubation after sedation and analgesia; patients with the narrowest tracheal diameter with 4-5 mm (3 cases with dyspnea Ⅱ, Shin grade Ⅳ) needed tracheotomy with local anesthesia by supplying oxygen with a mask; patients with the narrowest tracheal diameter<4 mm (3 cases with dyspnea Ⅲ, Shin grade Ⅲ) needed tracheotomy with extracorporeal circulation. Results: Respiratory passages for general anesthesia were safely established in all 14 patients, of whom 12 cases with differentiated thyroid carcinoma were treated with surgery, and 2 cases with undifferentiated thyroid carcinoma and B-cell lymphoma was treated with tracheotomy and then treated with chemotherapy in the Oncology or Hematology Department. All patients were followed-up for 2-22 months and survived without tumors, but one patient with undifferentiated carcinoma survived for 3 months. Conclusion: Respiratory passage can be established quickly and safe in advanced thyroid malignant tumor. This provides a necessary safety for patients who are needed surgical treatment and also an opportunity for patients undergoing other treatments.

[Clinicopathological features of mature T/NK cell lymphoma with aberrant CD20 or CD79α expression].

Objective: To investigate the clinicopathological characteristics and prognosis of mature T/NK cell lymphomas with aberrant CD20 or CD79α expression. Methods: A retrospective analysis of 641 cases of mature T/NK cell lymphoma diagnosed from January 2014 to December 2020 was performed, and 14 cases of CD20-positive and one case of CD79α-positive mature T/NK-cell lymphoma were identified. Histological examination, immunohistochemical characterization, in situ hybridization for Epstein-Barr virus encoded early RNA (EBER), and PCR testing for immunoglobulin and T cell receptor (TCR) gene rearrangements were performed. Clinicopathological characteristics of these lymphomas were analyzed. Results: There were 13 males and 2 females, with a median age of 56 years. There were 8 cases of peripheral T-cell lymphoma, not otherwise specified (PTCL-NOS), 3 cases of extranodal NK/T-cell lymphoma, nasal type (ENKTCL), 2 cases of monomorphic epitheliotropic intestinal T-cell lymphoma (MEITL) and 2 cases of angioimmunoblastic T-cell lymphoma (AITL). Twelve cases were stage Ⅲ or Ⅳ lymphomas. The prognosis was overall poor. The histology, immunophenotype and TCR gene rearrangement were not significantly different from the corresponding types of lymphoma. Ki-67 proliferation index was over 70% in all cases. The expression of CD20 or CD79α was weak and heterogeneous. All 15 case of Ig gene rearrangement were polyclonal. Conclusions: Mature T/NK cell lymphoma with abnormal expression of CD20 or CD79α is rare, commonly found in advanced stage, and associated with poor prognosis. The expression of CD20 or CD79α in these cases is weaker than the corresponding mature T/NK cell lymphomas, while its proliferation index is higher. Histomorphology, extensive immunoprofiling and molecular detection are required for accurate diagnosis.

[Clinicopathological features and BRAF V600E and MYD88 L265P mutation status of nodal marginal zone lymphoma].

Objective: To investigate the clinicopathological features as well as BRAF V600E and MYD88 L265P mutation status of nodal marginal zone B cell lymphoma (NMZL). Methods: Thirty-two cases of NMZL were diagnosed from September 2009 to February 2021 at the Henan Provincial People's Hospital and Peking University School of Basic Medical Sciences. The clinicopathologic characteristics were obtained and analyzed. BRAF V600E and MYD88 L265P mutation status were identified using PCR and Sanger sequencing, respectively. Results: There were 20 males and 12 females patients with a median age of 69 years (ranging 36-82 years). The most prevalent clinical manifestation was multiple lymph nodes enlargement in head and neck (22/32, 68.8%), followed by inguinal (12/32, 37.5%), axillary (11/32, 34.4%), mediastinum (5/32, 15.6%) and retroperitoneal lymph nodes (4/32, 12.5%). Most of the patients were in Ann Arbor stage Ⅰ/Ⅱ (21 cases). The morphologic features included diffuse (24/32, 75.0%), nodular (5/32, 15.6%), interfollicular (2/32,6.3%) and perifollicular (1/32,3.1%) types. The tumor cells showed monocyte-like, centrocyte-like, small lymphocyte-like and plasma cell-like differentiation. Immunophenotyping revealed diffuse expression of CD20 in all tumor cells, whereas CD43 (11/32, 34.4%), bcl-2 (20/32, 62.5%), MNDA (13/32, 40.6%) and CD5 (2/32, 6.3%) were partially expressed. Ki-67 proliferation index varied from 10% to 40%. BRAF V600E mutation was found in two cases (2/32, 6.3%), but MYD88 L265P mutation was not detected. Eighteen patients survived and three died at the end of follow-up period which ranged 6 to 110 months. Conclusions: The morphologic features of NMZL varies across individuals, it should be differentiated from various B-cell lymphomas; however immunological biomarkers with high specificity for NMZL are still lacking. No MYD88 L265P mutation is found in NMZL. Some cases may harbor BRAF V600E mutation and yet the prevalence remains indeterminate; further researches are warranted.

[Research advances on signaling pathways affecting sweat gland development and their involvement in the reconstitution of sweat adenoid cells in vitro].

The damage of sweat glands in patients with extensive deep burns results in the loss of thermoregulation, which seriously affects the quality of life of patients. At present, there are many researches on the repair of sweat gland function, but the mechanism of human sweat gland development has not been fully clarified. More and more studies have shown that the cascaded pathways of Wnt/ß-catenin, ecto- dysplasin A/ectodysplasin A receptor/nuclear factor-κB, sonic hedgehog, and forkhead box transcription factor jointly affect the development of sweat glands, and it has been reported that the cascaded signaling pathways can be used to achieve the reconstruction of sweat adenoid cells in vitro. This article reviews the signaling pathways that affect the development of sweat glands and their involvement in the reconstruction of sweat adenoid cells in vitro.

[Extranodal nasal type natural killer/T-cell lymphoma of the digestive system: a clinicopathological study of thirteen cases].

Objective: To investigate the clinicopathological features, and diagnostic and differential diagnostic characteristics of extranodal nasal type natural killer/T-cell lymphoma (ENKTCL) of the digestive system. Methods: Thirteen cases of ENKTCL in the digestive system were collected at the Henan Provincial People's Hospital, Zhengzhou, China, from August 2000 to August 2020. The histopathological, immunohistochemical and in situ hybridization features were analyzed, as well as those of T-cell receptor (TCR) gene rearrangement in some cases. The patients were followed up. Results: There were 11 males and 2 females. The age ranged from 28 to 80 years (median=53 years). Seven cases were present in the colorectum, and 3 cases were present in the small intestine. The other three cases were in stomach, gallbladder and liver (one case each). The main clinical symptoms were fever, and abdominal pain, often accompanied by fatigue, diarrhea, hematochezia, elevated serum albumin, elevated lactate dehydrogenase, and increased peripheral blood EB virus DNA copy. Histologically, the tumor accompanied by a heavy admixture of inflammatory cells (small lymphocytes, plasma cells and histiocytes). There was diffuse dense tumor cell infiltrate, with prominent coagulative necrosis. The lymphomatous infiltrate had angiocentric and angio-necrotic changes. Immunohistochemically, lymphoid cells expressed CD3 in all cases. Some of them showed weakened/absent other T cell markers, while all of them expressed CD56 except 1 case. A few of the cases showed CD4-/CD8+ killer T cell phenotypes. In situ hybridization showed EB virus encoded RNA (EBER) was positive in all cases. Clonal TCR gene rearrangement was not detected in all 7 cases tested. The median survival time was 9 months. Conclusions: ENKTCL of the digestive system is extremely rare. It often predisposes the patients to acute abdomen such as perforation of the gastrointestinal tract. The treatment outcomes are dismal, and the prognosis is poor. Clinical and imaging studies are often non-specific. It is also easy to be misdiagnosed as non-specific ulcers. Combined with immunohistochemistry, in situ hybridization and TCR gene rearrangement analysis and better understanding of this tumor's clinicopathological characteristics can help improve its diagnosis and early treatment.

Mucin 5AC is significantly upregulated in exosomes from the nasal lavage fluid and may promote the expression of COX-2, VEGF and MMP-9: an implication in nasal polyp pathogenesis.

BACKGROUND: Exosomes are critical mediators of intercellular communication and could be involved in many human diseases; however, little is known about the role of exosomes in nasal polyps (NP). METHODS: Exosomes in nasal lavage fluids (NLF) were isolated by ultracentrifugation. Exosome identity was validated by nanoparticle tracking analysis (NTA), transmission electron microscopy (TEM) and specific exosomal markers. The exosome proteome was revealed by LC-MS/MS, and the expression of the candidate exosomal protein, mucin 5AC, was confirmed by Western blot analysis and immunohistochemistry (IHC). Cellular uptake of the exosomes was monitored by fluorescence confocal microscopy and the ensuing effects on COX-2, VEGF and MMP-2/MMP-9 were determined by Western blotting, ELISA and gelatin zymography, respectively. RESULTS: Mass spectrometry analysis and subsequent verification by Western blotting identified that mucin 5AC was significantly upregulated in exosomes from NLFs of NP patients. Moreover, the expression of mucin 5AC was increased in the tissue specimens of the NP patients. Functional assays suggest that the mucin 5 AC-enriched exosomes could be effectively taken up by chronic rhinosinusitis without NP (CRSsNP)-derived fibroblasts, the control cells, resulting in a significant increase in the expression of COX-2, VEGF and MMP-9. CONCLUSIONS: Mucin 5AC, the major airway mucin, cannot only be carried and transferred by nasal exosomes, but may also promote tissue remodeling and angiogenesis and thus could be a potential therapeutic target of NP.

[Efficacy and safety of PD-1 inhibitor combined with chemotherapy in the primary treatment of phase â ¢/â £ extranodal nasal-type natural killer/T cell lymphoma].

The data of 9 patients with stage Ⅲ/Ⅳ extranodal nasal-type natural killer/T cell lymphoma from August 2019 to August 2020 in People's Hospital of Zhengzhou University was retrospectively analyzed. All the patients were treated with the programmed cell death-1 (PD-1) inhibitor combined with P-GemoX-DEX (gemcitabine+oxaliplatin+dexamethasone+peraspartase) regimen as the first-line treatment. After 4 cycles of treatment, positron emission tomography/computed tomography (PET/CT) was used to evaluate the curative effect, and adverse reactions were also observed. The median follow-up time was 7 months. The overall response rate, complete and partial remission rate was 9/9, 6/9 and 3/9, respectively. The main adverse event was hematological toxicity, with 6 cases of grade Ⅰ/Ⅱ neutropenia, and no immune-related adverse events were reported.

Probing molecular mechanism of inhibitor bindings to bromodomain-containing protein 4 based on molecular dynamics simulations and principal component analysis.

It is well known that bromodomain-containing protein 4 (BRD4) has been thought as a promising target utilized for treating various human diseases, such as inflammatory disorders, malignant tumours, acute myelogenous leukaemia (AML), bone diseases, etc. For this study, molecular dynamics (MD) simulations, binding free energy calculations, and principal component analysis (PCA) were integrated together to uncover binding modes of inhibitors 8P9, 8PU, and 8PX to BRD4(1). The results obtained from binding free energy calculations show that van der Waals interactions act as the main regulator in bindings of inhibitors to BRD4(1). The information stemming from PCA reveals that inhibitor associations extremely affect conformational changes, internal dynamics, and movement patterns of BRD4(1). Residue-based free energy decomposition method was wielded to unveil contributions of independent residues to inhibitor bindings and the data signify that hydrogen bonding interactions and hydrophobic interactions are decisive factors affecting bindings of inhibitors to BRD4(1). Meanwhile, eight residues Trp81, Pro82, Val87, Leu92, Leu94, Cys136, Asn140, and Ile146 are recognized as the common hot interaction spots of three inhibitors with BRD4(1). The results from this work are expected to provide a meaningfully theoretical guidance for design and development of effective inhibitors inhibiting of the activity of BRD4.

Revealing binding selectivity of inhibitors toward bromodomain-containing proteins 2 and 4 using multiple short molecular dynamics simulations and free energy analyses.

Emerging evidences indicate bromodomain-containing proteins 2 and 4 (BRD2 and BRD4) play critical roles in cancers, inflammations, cardiovascular diseases and other pathologies. Multiple short molecular dynamics (MSMD) simulations combined with molecular mechanics generalized Born surface area (MM-GBSA) method were applied to investigate the binding selectivity of three inhibitors 87D, 88M and 89G towards BRD2 over BRD4. The root-mean-square fluctuation (RMSF) analysis indicates that the structural flexibility of BRD4 is stronger than that of BRD2. Moreover the calculated distances between the Cα atoms in the centres of the ZA_loop and BC_loop of BRD4 are also bigger than that of BRD2. The rank of binding free energies calculated using MM-GBSA method agrees well with that determined by experimental data. The results show that 87D can bind more favourably to BRD2 than BRD4, while 88M has better selectivity on BRD4 over BRD2. Residue-based free-energy decomposition method was utilized to estimate the inhibitor-residue interaction spectrum and the results not only identify the hot interaction spots of inhibitors with BRD2 and BRD4, but also demonstrate that several common residues, including (W370, W374), (P371, P375), (V376, V380) and (L381, L385) belonging to (BRD2, BRD4), generate significant binding difference of inhibitors to BRD2 and BRD4.

Molecular mechanism of inhibitor bindings to bromodomain-containing protein 9 explored based on molecular dynamics simulations and calculations of binding free energies.

Recently, bromodomain-containing protein 9 (BRD9) has been a prospective therapeutic target for anticancer drug design. Molecular dynamics (MD) simulations combined with molecular mechanics generalized Born surface area (MM-GBSA) method were adopted to explore binding modes of three inhibitors (5SW, 5U2, and 5U6) to BRD9 and identify the hot spot of the inhibitor-BRD9 binding. The results indicate that the inhibitor 5SW has the strongest binding ability to BRD9 among the current three inhibitors. Furthermore, the rank of the binding free energies predicted by MM-GBSA approach agrees with that determined by the experimental values. In addition, inhibitor-residue interactions were computed by using residue-based free-energy decomposition method and the results suggest that residue His42 produces the CH-H interactions, residues Asn100, Ile53 and Val49 produce the CH-[Formula: see text] interactions with three inhibitors and Tyr106, Phe45 and Phe44 generate the π-π interactions with inhibitors. Notably, the residue Asn140 forms hydrogen bonding interactions with three inhibitors. This research is expected to provide useful molecular basis and dynamics information at atomic levels for the design of potent inhibitors inhibiting the activity of BRD9.