Indoleamine 2,3‐dioxygenase 1 (IDO1) is a key enzyme associated with immunomodulation through its regulation of the tryptophan‐kynurenine (Kyn) pathway in advanced cancers, including metastatic renal cell carcinoma (mRCC). However, the failure of IDO1 inhibitors when used in combination with immune checkpoint inhibitors (ICIs), as observed in clinical trials, raises a number of questions. This study aimed to investigate the association of tryptophan 2,3‐dioxygenase (TDO) and IDO1 with cancer development and resistance to immunotherapy in patients with RCC. In our analysis of RCC tissue samples, tissue Kyn levels were elevated in advanced‐stage RCC and correlated well with TDO expression levels in RCC tumor cells. In patients with mRCC, TDO rather than IDO1 was expressed in RCC tumor cells, showing a strong association with Kyn expression. Furthermore, immunohistochemical staining of TDO was strongly associated with the staining intensity of forkhead box P3, as well as ICI therapy response and survival in patients with mRCC. Our study is the first to show that TDO expression in tumor tissues is associated with progression and survival, confirming its potential as a predictive biomarker of primary resistance to immunotherapy in patients with mRCC. Our findings suggest that strategies aimed at inhibiting TDO, rather than IDO1, in combination with ICI therapy may aid in the control of mRCC progression.

Hepatic giant cell tumor is extremely rare, and only five cases have been reported of overt hepatocellular carcinoma, thus its histogenesis is controversial. Herein is reported a case of simultaneous hepatocellular carcinoma and osteoclast-like giant cell tumor in a single tumor. A liver tumor was found in a 74-year-old woman. Histologically the tumor consisted of two distinct components: mononuclear and multinuclear giant cells with osteoclastic giant cells, and a conventional hepatocellular carcinoma. The boundary between the two components showed transitional features. Immunohistochemistry showed that the osteoclast-like giant cells were CD68 and vimentin positive, but cytokeratin and AFP negative, while spindle-shaped cells were positive only for vimentin. In a portion of the hepatocellular carcinoma the cells were cytokeratin-8 and AFP positive. Ki-67 positivity was 10% for the hepatocellular carcinoma, 60% for the spindle-shaped cells, and 0% for the giant cells. It is possible that the tumor might have had a hepatocellular carcinoma origin, given the more highly proliferative sarcomatous changes and reactive osteoclast-like cells. This case provides a clue to the histogenesis of hepatic giant cell tumors.

Objectives To assess the impact of two cycles of neoadjuvant chemotherapy (NAC) in patients who underwent nephroureterectomy for high‐risk cN0M0 upper tract urothelial carcinoma (UTUC), and to evaluate the efficacy of NAC in patients with localised disease (≤cT2). Patients and Methods We retrospectively analysed patients with high‐risk cN0M0 UTUC who received NAC followed by surgery, compared with a matched cohort who underwent initial surgery at Fujita Health University during 2005–2019. Baseline and tumour characteristics, overall survival (OS), cancer‐specific survival (CSS), and recurrence‐free survival (RFS) were compared between the cohorts. Cox proportional hazards models were used to identify predictors of survival. Results There were 117 and 67 patients in the study group and the control group, respectively. Significantly higher pathological downstaging (pDS) and lower lymphovascular invasion (LVI) were observed in the study group than in the control group (48% vs 22%, P = 0.008 and 29% vs 46%, P = 0.045, respectively). The NAC group had significantly better 5‐year OS (79% vs 53%, P = 0.003), 5‐year CSS (84% vs 66%, P = 0.008), and 5‐year RFS (80% vs 61%, P = 0.001) than the control group. The OS benefit of NAC was observed even in patients with localised (≤cT2) disease (P = 0.019). Patients with LVI showed significantly worse CSS both in pathologically locally advanced (≥pT3) and in localised (≤pT2) tumours (P = 0.048 and P = 0.018, respectively). Multivariate analysis identified LVI, NAC, and pDS as independent predictors of OS. Male sex and post‐NAC LVI were identified as predictors of worse survival in patients who underwent NAC. Conclusions Two cycles of NAC improved the survival of patients with high‐risk UTUC, even in patients with localised disease. Although two cycles of NAC appear to be effective in cN0M0 high‐risk UTUC including localised disease, additional larger sample size multicentre prospective studies comparing short‐course NAC regimens followed by surgery and surgery alone are required.

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Abbreviations & Acronyms ASA = American Society of Anesthesiologists BMI = body mass index CRP = C-reactive protein EBL = estimated blood loss ECUD = extracorporeal urinary diversion ERAS = enhanced recovery after surgery G-8 = Geriatric-8 GI = gastrointestinal ICUD = intracorporeal urinary diversion IQR = interquartile range iRARC = RARC with ICUD LOS = length of hospital stay MIBC = muscle invasive bladder cancer NAC = neoadjuvant chemotherapy NMIBC = nonmuscle invasive bladder cancer POI = postoperative ileus RARC = robot-assisted radical cystectomy RC = radical cystectomy ROC = receiver operating characteristic WBC = white blood cells