Renal cell carcinoma is one of the most common malignant tumors of the urinary system.Its pronounced heterogeneity plays a crucial role in disease progression, treatment responses, and clinical outcomes.This review focuses on the heterogeneity of the tumor microenvironment in renal cell carcinoma, summarizing the key cellular interactions, the evolution of immunosuppressive states, and the reciprocal regulation between tumor and stromal components.The paper further discusses the clinical impacts of heterogeneity on immuno-targeted combination therapy, along with the application of emerging technologies, such as single-cell sequencing and spatial transcriptomics, so as to provide theoretical insights and practical guidance for the precision therapy for renal cell carcinoma.

OBJECTIVE: To explore the differences in perioperative clinical and pathological characteristics of patients with different pathological types of prostate cancer undergoing radical prostatectomy, and to analyze the influencing factors that may affect the extraglandular invasion of ductal adenocarcinoma of the prostate. METHODS: Retrospective collection was made of the radical prostatectomy patients who were admitted to Peking University Third Hospital from December 2011 to April 2021. The patients were screened based on inclusion criteria to obtain basic clinical features and postoperative pathological results. According to the pathological results, the patients were divided into ductal adenocarcinoma group (mixed with ductal adenocarcinoma) and acinar adenocarcinoma group, and a 1 ∶1 propensity score matching was performed to compare the differences in clinical characteristics between the two groups. Univariate and multivariate analyses of the factors related to extraglandular invasion were performed in the matched ductal adenocarcinoma groups. RESULTS: A total of 764 patients with prostate cancer were enrolled in this study, of which 62 patients were confirmed to have ductal adenocarcinoma components by postoperative pathology. There was a statistically significant difference in the proportion of the patients with a history of diabetes in baseline characteristics between the two groups before propensity score matching (29.5% vs. 17.7%, P=0.027). A total of 61 patients with simple acinar adenocarcinoma were successfully matched with the patients with ductal adenocarcinoma, and there was no statistically significant difference in baseline characteristics between the two groups after matching (P>0.05). The comparison of perioperative clinical and pathological features showed that International Society of Urology Pathology (ISUP) grade (P=0.003), pT stage (P=0.004), extraglandular invasion rate (P=0.018) and vascular thrombus rate (P=0.019) in ductal adenocarcinoma group were significantly higher than those in simple acinous adenocarcinoma group. Univariate analysis of the influence factors of extraglandular invasion showed that prostate-specific antigen (PSA) level, prostate volume, ISUP grade, seminal vesicle invasion and perineural invasion might be the influencing factors of extraglandular invasion (P < 0.10). Binary Logistic regression analysis showed that perineural invasion was an independent factor of extraglandular invasion (OR=11.78, 95%CI: 1.97-70.56, P=0.007). CONCLUSION Prostatic ductal adenocarcinoma has a worse prognosis than simple acinar adenocarcinoma. Perineural invasion is the influencing factor of extraglandular invasion of ductal adenocarcinoma.
Humans ; Male ; Prostatic Neoplasms/surgery* ; Retrospective Studies ; Prostatectomy ; Neoplasm Invasiveness ; Middle Aged ; Aged ; Carcinoma, Ductal/surgery* ; Propensity Score ; Adenocarcinoma/surgery*

OBJECTIVE: To investigate the safety and prognostic factors influencing the treatment of upper urinary tract urothelial carcinoma (UTUC) combined with bladder cancer (BCa) by laparoscopic simultaneous radical cystectomy and nephroureterectomy (RCNU). METHODS: The clinical data of patients admitted to Peking University Third Hospital for laparoscopic RCNU surgery from January 2009 to September 2023 were analyzed retrospectively. Based on the same gender, age (±5 years), history of uroepithelial tumors, underlying diseases, T-stage, N-stage, M-stage, American Society of Anesthesiologists (ASA) score, Charlson comorbidity index, and body mass index (BMI) (±5), 34 patients with RCNU were matched 1 ∶1 with patients with bladder cancer who underwent laparoscopic radical cystectomy (RC) alone. Kaplan-Meier survival analysis was used to calculate patient survival, and Cox proportional regression risk model was used to analyze clinical factors affecting prognosis. RESULTS: Of the 68 patients enrolled, the follow-up rate was 100% with a median follow-up time of 27.0 (11.7, 60.2) months. Comparison of intraoperative conditions (including operation time, estimated intraoperative bleeding, intra-operative blood transfusion, etc.) between the two groups of patients showed no significant difference (P>0.05). Comparison of preoperative creatinine and postoperative creatinine between the two groups of patients showed significant differences (P < 0.05). The perioperative Clavien grade Ⅲ-Ⅳ complication rates were 2.9% (1/34) in the RC group and 5.9% (2/34) in the RCNU group. There was no significant difference in terms of perioperative complications between the two groups. Overall survival was significantly lower in the patients receiving RCNU compared with the matched group receiving RC alone (P < 0.05). Cox regression analysis suggested that two factors, high N stage and high postoperative creatinine, were independent risk factors affecting the prognosis of patients in the 2 groups (P < 0.05). CONCLUSION The overall survival prognosis of patients undergoing RCNU surgery was worse compared with laparoscopic RC surgery alone during the same period. There was no clinically significant difference between the two groups in terms of operation time, intraoperative bleeding, and perioperative complications, and there were clinically significant differences in preoperative renal function and post-operative renal function.
Humans ; Laparoscopy/methods* ; Nephroureterectomy/methods* ; Cystectomy/methods* ; Prognosis ; Male ; Retrospective Studies ; Female ; Urinary Bladder Neoplasms/mortality* ; Middle Aged ; Aged

Mycophenolic acid (MPA), the active moiety of both mycophenolate mofetil (MMF) and enteric-coated mycophenolate sodium (EC-MPS), serves as a primary immunosuppressant for maintaining solid organ transplants. Therapeutic drug monitoring (TDM) enhances treatment outcomes through tailored approaches. This study aimed to develop an evidence-based guideline for MPA TDM, facilitating its rational application in clinical settings. The guideline plan was drawn from the Institute of Medicine and World Health Organization (WHO) guidelines. Using the Delphi method, clinical questions and outcome indicators were generated. Systematic reviews, Grading of Recommendations Assessment, Development, and Evaluation (GRADE) evidence quality evaluations, expert opinions, and patient values guided evidence-based suggestions for the guideline. External reviews further refined the recommendations. The guideline for the TDM of MPA (IPGRP-2020CN099) consists of four sections and 16 recommendations encompassing target populations, monitoring strategies, dosage regimens, and influencing factors. High-risk populations, timing of TDM, area under the curve (AUC) versus trough concentration (C₀), target concentration ranges, monitoring frequency, and analytical methods are addressed. Formulation-specific recommendations, initial dosage regimens, populations with unique considerations, pharmacokinetic-informed dosing, body weight factors, pharmacogenetics, and drug‍-‍drug interactions are covered. The evidence-based guideline offers a comprehensive recommendation for solid organ transplant recipients undergoing MPA therapy, promoting standardization of MPA TDM, and enhancing treatment efficacy and safety.
Mycophenolic Acid/administration & dosage* ; Drug Monitoring/methods* ; Humans ; Organ Transplantation ; Immunosuppressive Agents/administration & dosage* ; Delphi Technique

A 34-year-old male patient was admitted to the hospital on October 6, 2023 due to fall from a high place. Physical examination showed blood pressure 96/53 mmHg (1 mmHg=0.133 kPa), heart rate of 105 beats/min, slight bulge in the right kidney area, and positive percussion pain in the right kidney area. CT examination showed complete rupture of the lower pole of the right kidney, thrombosis of the right renal vein, and contusion and laceration of the right posterior lobe of the liver. According to the American Association for the Surgery of Trauma renal injury classification, he was diagnosed as grade Ⅳ renal rupture. After blood transfusion and fluid infusion, vital signs were stable. Laparoscopic nephrectomy plus renal vein thrombectomy plus liver rupture repair were performed. The operation took 90 minutes, and about 300 ml of blood clots and fresh blood were aspirated during the operation. The patient's vital signs were stable after the operation, and he could get out of bed 3 days after the operation. CT reexamination 1 month after the operation showed right kidney resected and the liver healed well. This operation is feasible if the patient's vital signs are stable, with the advantages of small surgical incision, short operation time, less bleeding, fast postoperative recovery and good surgical effect.

Objective:To explore the feasibility of radiomics-based quantitative analysis for molecular pathological subtyping in renal computed tomography angiography（CTA）and to establish a predictive model for renal mass subgroups.Methods:We retrospectively enrolled 535 patients with renal masses，including malignant lesions［223 clear cell renal cell carcinomas（ccRCC），84 papillary renal cell carcinomas（pRCC），113 chromophobe renal cell carcinomas（chrRCC）］and benign lesions［62 fat-poor angiomyolipomas（fpAML），53 oncocytomas］. There were 195 males and 340 females，with a median age of 52（range 49 to 80）years old. All patients underwent standard renal CTA prior to surgery. Radiomics features were extracted from CTA images. Data were categorized into six subgroups（malignant vs. benign，ccRCC vs. other renal masses，pRCC vs. other renal masses，chrRCC vs. other renal masses，fpAML vs. other renal masses，oncocytomas vs. other renal masses）. The dataset was randomised into training and validation cohorts by dividing the patients in a 2∶1 ratio. A machine learning-based predictive model（Radiomics-CTA）was developed using selected radiomic features in the training cohort. The model efficacy was assessed in the training cohort and validation cohort separately by plotting subject operating characteristic（ROC）curves，calculating area under the curve（AUC），and plotting clinical decision curves for model efficacy assessment.Results:For the malignant subgroup，Radiomics-CTA achieved area under the receiver operating characteristic curve（AUC）values of 0.823（95% CI 0.751?0.894）and 0.833（95% CI 0.783?0.883）in the training and validation cohorts，respectively. For ccRCC identification，the model showed AUCs of 0.928（95% CI 0.89?0.955）and 0.925（95% CI 0.881?0.968）in the two cohorts. For the other subtypes identification，such as pRCC，chrRCC，fpAML，and oncocytomas，the model showed AUCs of 0.862（95% CI 0.826?0.898），0.882（95% CI 0.849?0.915），0.921（95% CI 0.898? 0.943），and 0.865（95% CI 0.787?0.944）in the training cohort，and the AUC of 0.823（95% CI 0.776?0.870），0.842（95% CI 0.754?0.929），0.930（95% CI 0.892?0.968）and 0.876（95% CI 0.847? 0.906）in the validation cohort . Radiomics-CTA outperformed senior radiologists in diagnosing ccRCC［87.1%（466/535）vs. 83.2%（445/535）， P=0.03）］and chrRCC［82.1%（439/535）vs. 80.0（428/535）， P<0.01］. Conclusions:The Radiomics-CTA model can extract deep pathological information from CTA images through radiomics methods，and has the ability to distinguish pathological subtypes of renal tumors. It can also provide assistance for accurate diagnosis by radiologists to a certain extent.

Objective:To evaluate the safety and oncological outcomes of robot-assisted laparoscopic inferior vena cava(IVC)segmental resection in renal tumor with IVC tumor thrombus(IVCTT).Methods:Clinical data from renal tumor patients undergoing robot-assisted laparoscopic IVC segmental resection at Peking University Third Hospital from Jan.2021 to Feb.2025 were retrospectively analyzed.Data collection included baseline demographics,tumor characteristics,perioperative parameters,and follow-up outcomes.Surgical records and pathological reports were retrieved from the electronic medical record system.Continuous variables were presented as median(P25,P75),and categorical variables as frequency(percentage).Results:Forty-four patients were enrolled.The cohort comprised 31 malesand 13 females,with a median age of 62(55,68)years.Right-sided tumors were observed in 39 cases and left-sided in 5 cases.Median tumor diameter was 8.1(6.1,10.1)cm.Mayo classifications included grade Ⅱ(n=37),Ⅲ(n=6),and Ⅳ(n=1).Neoadjuvant therapy was administered to 23 patients.Seventeen patients were complicated by IVC bland thrombus.Median operative time was 224.0(167.3,303.8)min,with intraoperative blood loss of 500.0(300.0,850.0)mL.Transfusion was administered to 19 patients,with a median blood transfusion of 800.0(400.0,1 200.0)mL.Postoperative complica-tions occurred in 25 cases(56.8％),classified as Clavien-Dindo grade Ⅰ(n=8)and grade Ⅱ(n=17).Procedure-specific complications included deep vein thrombosis(n=6),transfusion-requiring ane-mia(n=5),lower extremity edema(n=2),and pulmonary embolism(n=2),with no procedure-related mortality.Median postoperative serum creatinine was 116.0(86.5,157.5)μmnol/L.Pathological examination identified clear cell renal cell carcinoma as the predominant subtype,observed in 34 cases(77.3％).Pathological staging revealed T3b(n=12),T3c(n=29),and T4(n=3)disease,with nodal involvement(N1)in 8 cases and distant metastasis(M1)in 17.At a median follow-up of 10 months(range:1-49 months),cancer-specific mortality occurred in 3 patients,while 1 succumbed to other causes.Disease progression included pulmonary metastasis(n=5),hepatic metastasis(n=4),and local recurrence(n=4).Adjuvant therapy regimens comprised targeted-immunotherapy combina-tions(n=9)and targeted monotherapy(n=18).Conclusion:Robot-assisted laparoscopic I VC seg-mental resection achieves precise thrombus removal with confirmed short-term efficacy in renal tumor with IVCTT,though vigilance against vascular complications remains critical.

Objective:To review the clinicopathological features of TFE3-rearranged renal cell carcino-ma(TFE3-RCC)with venous tumor thrombus(VT)(TFE3-VT),to explore treatment strategies and to prognostic characteristics,and to provide diagnostic and therapeutic references for TFE3-VT patients.Methods:Patients who underwent surgery at Department of Urology,Peking University Third Hospital from January 2013 to January 2024 were enrolled,including three cohorts:Pathologically confirmed TFE3-VT patients,TFE3-RCC patients without VT(TFE3-non-VT),and non-TFE3-rearranged renal cell carcinoma patients with VT(non-TFE3-VT).Clinical history,imaging data,pathological data,and follow-up records were collected.Primary and secondary endpoints were progression-free survival(PFS)and overall survival(OS),respectively.(1)Baseline characteristics were compared between the TFE3-VT and TFE3-non-VT patients.Normally distributed continuous variables were expressed as mean±SD and compared using Student's t-test;non-normally distributed variables were expressed as M(P25,P75)and analyzed with Mann-Whitney U test;categorical variables were described as frequency and percentage[n(％)]and compared by x2 test or Fisher's exact test.(2)Clinical history,radiological presenta-tions,surgical data,and histopathological features of the TFE3-VT patients were comprehensively charac-terized.(3)Survival analysis was performed for the TFE3-VT patients.Follow-up data of the TFE3-VT patients were described in detail,and their survival outcomes were compared with the TFE3-non-VT and non-TFE3-VT patients.When compared with the TFE3-non-VT counterparts,Kaplan-Meier method was used to generate PFS and OS curves among:(1)the TFE3-RCC patients across clinical stages Ⅰ-Ⅳ;(2)TFE3-VT versus TFE3-non-VT cohorts;(3)stage Ⅲ subgroups of the TFE3-VT and TFE3-non-VT patients.Intergroup survival differences were statistically evaluated using Log-rank tests.For comparisons with the non-TFE3-VT patients,a 1∶1 propensity score matching(PSM)was implemented to balance baseline characteristics between the two cohorts.Post-matching Kaplan-Meier curves were generated to compare PFS and OS between the matched groups,with Log-rank tests employed to determine statistical significance of survival disparities.All statistical analyses were conducted with R software(v 4.2.3),and two-tailed P＜0.05 was considered statistically significant.Results:The study included 45 TFE3-RCC patients:13 TFE3-VT and 32 TFE3-non-VT cases.Additionally,523 non-TFE3-VT patients were enrolled.Among the 13 TFE3-VT patients,9 were female(69.2％)and 4 male(30.8％),with a mean age of(37.9±14.4)years,mean BMI of(22.2±3.5)kg/m2,median age-adjusted Charlson comorbidity index(aCCI)of 1.0(0.0,1.0),and preoperative creatinine level of(75.3±15.9)μmol/L;tumors were located in the left kidney in 7 patients(53.8％)and right kidney in 6(46.2％);preoperative distant metastasis(M1 stage)was present in 6 patients(46.2％),while 7(53.8％)showed no metastasis;VT distribution by Mayo level comprised 7 cases(53.8％)at level 0,1 case each at levels Ⅰ and Ⅳ(7.7％respectively),and 2 cases each at levels Ⅱ and Ⅲ(15.4％respectively);surgical approaches comprised open surgery(n=2,15.4％),laparoscopic surgery(n=6,46.1％),and robot-assisted laparoscopic surgery(n=5,38.5％);mean operative time was(273±79)min,and intraoperative blood loss was(722±570)mL;mean maximum tumor diameter was(10.8±2.4)cm.All the 13 patients underwent TFE3 protein immunohistochemistry(IHC)staining,with 7 confirmed by fluorescence in situ hybridization(FISH).Tumor recurrence or metastasis occurred in 11 patients(84.6％),and 9(69.2％)patients died during follow-up.Median PFS was 4 months(1 year PFS rate:31％),and median OS was 13 months(1 year OS rate:54％).Survival analysis of 45 TFE3-RCC pa-tients revealed statistically significant differences in PFS and OS across all the clinical stages(P＜0.001).The TFE3-VT patients exhibited significantly worse PFS and OS than the TFE3-non-VT patients(P＜0.001),with persistent significance in stage Ⅲ subgroup analysis(P＜0.05).After PSM,TFE3-VT pa-tients showed significantly inferior PFS compared with non-TFE3-VT(P=0.01),though no significant difference was shown between the OS curves(P=0.11).Conclusion:TFE3-VT predominantly occurs in young females with frequent preoperative metastases.Strongly-positive staining of TFE3 protein in IHC stai-ning and red-green split signals in FISH tests are reliable diagnostic markers.TFE3-VT patients exhibit in-ferior survival compared with TFE3-non-VT patients and earlier progression than non-TFE3-VT patients.

Objective:To review and summarize the experience of robot-assisted laparoscopic trans-plant nephrectomy,share the surgical steps and technical key points,and provide a reference for clinical practice.Methods:A retrospective analysis was conducted on the perioperative data of 5 patients who underwent robot-assisted laparoscopic donor nephrectomy at Peking University Third Hospital from August 2023 to December 2024.The surgical steps and key points were summarized.The continuous variables were described by medians(ranges).Results:A total of 5 patients were included in the analysis,of whom 2 were male and 3 were female.The median age of the patients was 37(31-68)years.The me-dian time from kidney transplantation to donor nephrectomy was 10(3-22)years.The indications for donor nephrectomy included recurrent hematuria,abdominal pain,malignant tumor of the transplanted kidney,and recurrent infection with hydronephrosis of the transplanted kidney.The excised transplanted kidneys from all the 5 patients had a single renal artery and a single renal vein.The median operation time was 212(145-351)min,the median blood loss was 300(20-500)mL,and the median post-operative hospital stay was 7(4-25)days.Only 1 patient experienced intraoperative complications,who experienced an external iliac artery injury during the operation and underwent suture repair.No pa-tient died during the perioperative period.Postoperative pathological results showed that 3 patients had end-stage non-functional kidneys,1 patient had BK virus-associated urothelial carcinoma,and 1 patient had chronic pyelonephritis with renal parenchymal atrophy.Conclusion:Robot-assisted laparoscopic transplant nephrectomy as a new surgical approach is feasible and safe.Compared with traditional open transplant nephrectomy,its advantage lies in the ability to directly observe and prioritize the management of the renal pedicle of the transplanted kidney,while completely freeing and removing the transplanted kidney outside the renal capsule.With the continuous accumulation of experience,this surgical technique is expected to become a powerful alternative to traditional open transplant nephrectomy.

Objective:To explore the clinical characteristics and prognostic factors of primary bladder adenocarcinoma（ACB）.Methods:The clinical data of 33 patients with primary ACB who underwent surgical treatment in the Department of Urology of Peking University Third Hospital from July 2003 to January 2024 were retrospectively analyzed. There were 5 females and 28 males，with an average age of（61.3 ± 11.5）years. Twelve patients had comorbidities（6 hypertension，2 coronary heart disease，5 diabetes mellitus，and 3 cerebrovascular diseases）and 12 had a smoking history. The mean body mass index（BMI）was（24.8 ± 3.2）kg/m 2. The maximum tumor diameter measured by enhanced computed tomography（CT）was（29.7 ± 12.7）mm. The preoperative neutrophil-to-lymphocyte ratio（NLR）was 3.4 ± 3.2，and the systemic immune-inflammation index（SII）was（582 ± 496）× 10 9/L.Patients were divided into two groups according to the surgical approach：the radical cystectomy group（ n = 23）and the bladder-sparing group（ n = 10）. For the radical cystectomy group，there were 19 males and 4 females，with a mean age of（59.9 ± 12.6）years. Five patients had comorbidities（3 hypertension，1 coronary heart disease，1 diabetes mellitus，and 2 cerebrovascular diseases）. Eight patients had a smoking history，with a mean BMI of（25.2 ± 3.5）kg/m 2. The maximum tumor diameter was（33.6 ± 10.9）mm，the preoperative NLR was 3.5 ± 3.5，and the SII was（618 ± 558）× 10 9/L. For the bladder-sparing group，there were 9 males and 1 female，with a mean age of（64.5 ± 8.2）years. Seven patients had comorbidities（3 hypertension，1 coronary heart disease，4 diabetes mellitus，and 1 cerebrovascular diseases）. Four patients had a smoking history，with a mean BMI of（23.5 ± 2.3）kg/m 2. The maximum tumor diameter was（20.7 ± 12.5）mm，the preoperative NLR was 3.1 ± 2.2，and the SII was（501 ± 323）× 10 9/L. Statistically significant differences were observed between the two groups in terms of comorbidities（ P = 0.008）and maximum tumor diameter（ P = 0.006），while no significant differences were found in other data（ P > 0.05）. The Kaplan-Meier survival curve was drawn，and Cox regression was used to analyze the prognostic factors of progression-free survival（PFS）and overall survival（OS）of patients. Results:Among the 33 patients，low-grade adenocarcinoma and high-grade adenocarcinoma accounted for 60.6% and 39.4% respectively according to the postoperative pathology，and 3 patients had positive surgical margins. There were 22 cases of muscle-invasive bladder adenocarcinoma，5 cases of lymph node metastasis，and 1 case of distant metastasis. The patients in tumor stages Ⅰ—Ⅳ were 9 cases（27.3%），8 cases（24.2%），7 cases（21.2%），and 9 cases（27.3%）respectively. Nine patients received postoperative adjuvant therapy，including 6 with adjuvant chemotherapy，2 with adjuvant chemotherapy combined with radiotherapy，and 1 with adjuvant immunotherapy. In the radical cystectomy group（ n = 23），there were 13 cases of low-grade and 10 cases of high-grade pathological grading，2 cases with positive margins，19 cases of muscle-invasive bladder adenocarcinoma，5 cases of lymph node metastasis，1 case of distant metastasis，and 5 patients received adjuvant therapy（4 cases of adjuvant chemotherapy，and 1 case of adjuvant immunotherapy）. In the bladder-sparing group（ n = 10），there were 7 cases of low-grade，3 cases of high-grade pathological grading，1 case with positive margins，3 cases of muscle-invasive bladder adenocarcinoma，zero lymph node or distant metastasis，and 4 patients received adjuvant therapy（2 cases of adjuvant chemotherapy，and 2 cases of combined adjuvant chemotherapy and radiotherapy）. A statistically significant difference was found in the proportion of muscle-invasive bladder adenocarcinoma between the two groups（ P = 0.006），while no significant differences were observed in other data（ P > 0.05）.The median follow-up duration of the patients was 28.0 months，the median PFS was 86.0 months，and the median OS was 90.0 months. The 2-year PFS and OS were 65.4% and 73.1% respectively. The 5-year PFS and OS were 54.2% and 56.5% respectively. The Kaplan-Meier survival analysis showed that there were no significant differences in PFS（ P = 0.777）and OS（ P = 0.585）between the radical cystectomy group and the bladder-preserving group. Female（ P = 0.011），BMI < 25 kg/m2（ P = 0.038），and positive surgical margins（ P < 0.01）were associated with poorer PFS. Aged ≥ 70 years（ P = 0.003），lymph node metastasis（ P = 0.041），and positive surgical margins（ P = 0.025）were associated with poorer OS，and patients in the adjuvant therapy group had better OS（ P = 0.005）. Multivariate Cox regression analysis indicated that positive surgical margins（HR 10.2， P = 0.012）were an independent impact factor for PFS，and positive surgical margins（HR 39.8， P = 0.001）and adjuvant therapy（HR 0.12， P = 0.021）were independent impact factors for OS. Conclusions:Positive surgical margins and adjuvant therapy are independent impact factors for the prognosis of patients with primary ACB.