Notch signaling suppresses neuroendocrine differentiation and alters the immune microenvironment in advanced prostate cancer.

Notch signaling can have either an oncogenic or tumor suppressive function in cancer depending on the cancer type and cellular context. While Notch can be oncogenic in early prostate cancer, we identified significant downregulation of the Notch pathway during prostate cancer progression from adenocarcinoma to neuroendocrine prostate cancer where it functions as a tumor suppressor. Activation of Notch in neuroendocrine and Rb1/Trp53-deficient prostate cancer models led to phenotypic conversion towards a more indolent non-neuroendocrine state with glandular features and expression of luminal lineage markers. This was accompanied by up-regulation of MHC and type I interferon and immune cell infiltration. Overall, these data support Notch signaling as a suppressor of neuroendocrine differentiation in advanced prostate cancer and provides insights into how Notch signaling influences lineage plasticity and the tumor microenvironment.

Association Between Residual Urine Volume and Recurrence Among Patients at High Risk of Non-Muscle-Invasive Bladder Carcinoma With Versus Without Bacillus Calmette-Guérin Treatment.

Non-muscle-invasive bladder carcinoma often occurs in older adults, who often also have urinary dysfunction. The residual urine volume is an important indicator of urinary dysfunction. However, the impact of the residual urine volume on intravesical recurrence remains unclear. In the present study, we analyzed the data of 372 patients at high or very high risk of cancer progression according to the Japanese Urological Association classification who had undergone transurethral resection of a bladder tumor. In univariate analysis, postoperative absence of intravesical Bacillus Calmette-Guérin (BCG) induction was an independent risk factor for intravesical recurrence (hazard ratio 1.94, absence versus presence, p = 0.0019). The incidence of intravesical recurrence did not significantly differ between the mild, intermediate, and severe residual urine groups in the total cohort. Among the BCG-treated cohort, the three groups showed similar trends. Among the non-BCG-treated cohort, although the patients with more than 100 ml of residual urine tended to have more intravesical recurrence than patients with a smaller residual urine volume, this difference did not reach statistical significance. BCG treatment is recommended for patients at high risk of bladder carcinoma. Patients with a large residual urine volume without BCG treatment may be at high risk of intravesical recurrence.

Implications of unconventional histological subtypes on magnetic resonance imaging and oncological outcomes in patients who have undergone radical prostatectomy.

The prognostic significance of unconventional histology (UH) subtypes including intraductal carcinoma of the prostate (IDC-P), ductal adenocarcinoma, and cribriform pattern has been investigated for prostate cancer (PCa). However, little is known about magnetic resonance imaging (MRI) features and the oncological impact of tumor localization in localized PCa with UH. Clinical data of 211 patients with acinar adenocarcinoma (conventional histology [CH]) and 82 patients with UH who underwent robotic-assisted radical prostatectomy (RARP) were reviewed. Patients with UH are more likely to be older and have higher Gleason grade group, higher Prostate Imaging-Reporting and Data System (PI-RADS) v2.1 score, and larger tumor volume (TV) than those with CH. Multivariate analysis identified the presence of UH as an independent prognostic factor for progression-free survival (PFS) (hazard ration (HR) 2.41, 95% confidence interval (CI) 0.22-0.79, P = 0.0073). No significant difference in PFS was seen regarding tumor localization (transition zone [TZ] or peripheral zone [PZ]) in patients with UH (P = 0.8949), whereas PZ cancer showed shorter PFS in patients with CH (P = 0.0174). PCa with UH was associated with higher progression than PCa with CH among resection margin (RM)-negative cases (P < 0.0001). Further, increased PI-RADS v2.1 score did not correlate with larger TV in UH (P = 0.991), whereas a significant difference in TV was observed in CH (P < 0.0001). The prognostic significance of UH tumor was independent of tumor localization, and shorter PFS was observed even in RM-negative cases, indicating an aggressive subtype with micro-metastatic potential. Furthermore, UH tumors are more likely to harbor a large TV despite PI-RADS v2.1 score ≤ 3. These findings will help optimal perioperative management for PCa with UH.

The LAT1 inhibitor JPH203 suppresses the growth of castration-resistant prostate cancer through a CD24-mediated mechanism.

L-type amino acid transporter 1 (LAT1) is specifically expressed in many malignancies, contributes to the transport of essential amino acids, such as leucine, and regulates the mammalian target of rapamycin (mTOR) signaling pathway. We investigated the expression profile and functional role of LAT1 in prostate cancer using JPH203, a specific inhibitor of LAT1. LAT1 was highly expressed in castration-resistant prostate cancer (CRPC) cells, including C4-2 and PC-3 cells, but its expression level was low in castration-sensitive LNCaP cells. JPH203 significantly inhibited [14C] leucine uptake in CRPC cells but had no effect in LNCaP cells. JPH203 inhibited the proliferation, migration, and invasion of CRPC cells but not of LNCaP cells. In C4-2 cells, Cluster of differentiation (CD) 24 was identified by RNA sequencing as a novel downstream target of JPH203. CD24 was downregulated in a JPH203 concentration-dependent manner and suppressed activation of the Wnt/ß-catenin signaling pathway. Furthermore, an in vivo study showed that JPH203 inhibited the proliferation of C4-2 cells in a castration environment. The results of this study indicate that JPH203 may exert its antitumor effect in CRPC cells via mTOR and CD24.

Testosterone bounce predicts favorable prognoses for prostate cancer patients treated with degarelix.

BACKGROUND: To clarify the clinical roles of changes in testosterone (T) levels with a cut-off level of 20 ng/dL as predictive factors for prostate cancer patients treated with degarelix acetate. METHODS: A total of 120 prostate cancer patients who received hormone therapies with gonadotropin-releasing hormone antagonist degarelix acetate were retrospectively analyzed. The predictive values of nadir T levels, max T levels, T bounce, and other clinical factors were evaluated for overall survival (OS), cancer-specific survival (CSS), and progression-free survival (PFS). T bounce was defined as satisfying both nadir serum T levels of <20 ng/dL and max serum T levels of ≥20 ng/dL during hormone therapies. RESULTS: In 120 prostate cancer patients, 16 (13%) patients did not achieve nadir T < 20 ng/dL, and 76 (63%) patients had max T ≥ 20 ng/dL. The median times to nadir T and max T are 108 and 312 days, respectively. T bounce was shown in 60 (50%) patients and is associated with favorable prognoses both for OS (p = 0.0019) and CSS (p = 0.0013) but not for PFS (p = 0.92). While in the subgroup analyses of the patients with the progression of the first-line hormone therapies, T bounce predicts favorable OS (p = 0.0015) and CSS (p = 0.0013) after biochemical recurrence. CONCLUSIONS: The present study revealed that T bounce with cut-off levels of 20 ng/dL is a promising biomarker that predicts OS and CSS for prostate cancer patients treated with degarelix acetate.

Copy Number Gain in Androgen Receptors Predicts the Poor Prognosis in Japanese Castration-resistant Prostate Cancer.

BACKGROUND/AIM: The prognostic significance of androgen receptor amplification (AR amp) in cell-free DNA (cfDNA) was studied in Japanese patients with castration-resistant prostate cancer (CRPC). PATIENTS AND METHODS: A total of 120 serum samples were obtained from 38 patients with CRPC. Serum cfDNA was purified and the AR copy number was determined. Factors associated with progression-free survival (PFS) and overall survival (OS) were statistically investigated. RESULTS: The number of patients administered enzalutamide (Enza)/abiraterone (Abi)/docetaxel (DTX) was 33/25/11, respectively. The median PSA was 16.5 ng/ml. Thirty patients (79%) had bone metastases and three patients (7.9%) had lung metastases. The median follow-up was 655 days. The median initial AR copy number was 1.27 (1.10-11.50); an AR copy number of 1.27 or higher was defined as an AR-amp. Regarding PFS, the presence of AR-amp, Gleason score (GS), and ALP were significant factors in univariate analysis. In multivariate analysis, AR amplification was an independent prognostic factor (hazard ratio=7.7, p=0.0035). For OS, PSA and AR-amp were significant factors. In multivariate analysis, AR-amp (hazard ratio=4.65, p=0.0188) was the only independent prognostic factor. CONCLUSION: AR-amp was associated with high nadir PSA and low iPSA/PSA ratio. AR-amp was significantly associated with poor prognosis in Japanese patients with CRPC.

L-type amino acid transporter 1 inhibitor JPH203 prevents the growth of cabazitaxel-resistant prostate cancer by inhibiting cyclin-dependent kinase activity.

L-type amino acid transporter 1 (LAT1, SLC7A5) is an amino acid transporter expressed in various carcinomas, and it is postulated to play an important role in the proliferation of cancer cells through the uptake of essential amino acids. Cabazitaxel is a widely used anticancer drug for treating castration-resistant prostate cancer (CRPC); however, its effectiveness is lost when cancer cells acquire drug resistance. In this study, we investigated the expression of LAT1 and the effects of a LAT1-specific inhibitor, JPH203, in cabazitaxel-resistant prostate cancer cells. LAT1 was more highly expressed in the cabazitaxel-resistant strains than in the normal strains. Administration of JPH203 inhibited the growth, migration, and invasive ability of cabazitaxel-resistant strains in vitro. Phosphoproteomics using liquid chromatography-mass spectrometry to comprehensively investigate changes in phosphorylation due to JPH203 administration revealed that cell cycle-related pathways were affected by JPH203, and that JPH203 significantly reduced the kinase activity of cyclin-dependent kinases 1 and 2. Moreover, JPH203 inhibited the proliferation of cabazitaxel-resistant cells in vivo. Taken together, the present study results suggest that LAT1 might be a valuable therapeutic target in cabazitaxel-resistant prostate cancer.

Metabolic Syndrome Accelerates the Age-Related Increase of Intraductal Papillary Mucinous Neoplasm of the Pancreas.

OBJECTIVES: Aging is associated with a high prevalence of pancreatic cysts and intraductal papillary mucinous neoplasms (IPMNs). Metabolic syndrome (MS) may increase the risk of neoplasms, including those that develop in the pancreas. However, the influence of factors associated with MS on the development of IPMN remains unclear. METHODS: A total of 9363 patients who underwent abdominal ultrasound examinations between April 2012 and May 2013 were included in this study. Multivariate logistic regression analysis was performed to identify factors associated with the presence of IPMN by age. RESULTS: Pancreatic cysts were detected in 198 of 9363 patients, of whom 129 were found to have IPMNs. The presence of IPMN significantly correlated with age (10-year increments; odds ratio, 2.73; 95% CI, 2.28-3.29; P < 0.001). High body mass index, history of smoking, hyperlipidemia, hypertension, and MS were associated with a higher prevalence of IPMN with advancing age. In multivariate analysis, the presence of IPMN was more frequent in elderly patients with MS (odds ratio, 3.14; 95% CI, 3.14-6.72; P = 0.003). CONCLUSIONS: The present study suggests that the incidence of IPMN increases with age and is accelerated in the presence of MS.

A prospective randomized study of multimodal analgesia combined with single injection transversus abdominis plane block versus epidural analgesia against postoperative pain after laparoscopic colon cancer surgery.

PURPOSE: Transversus abdominis plane (TAP) block is a safe, effective, and promising analgesic procedure, but TAP block only cannot overcome postoperative pain. We conducted a prospective randomized study to evaluate postoperative pain control using multimodal analgesia (MA) combined with a single injection TAP block compared with epidural analgesia (EA) after laparoscopic colon cancer surgery. METHODS: Sixty-seven patients scheduled for elective laparoscopic colon cancer surgery were enrolled in this study and randomized into EA and MA groups. The primary endpoint was the frequency of additional analgesic use until postoperative day (POD) 2. The VAS score, blood pressure, time to bowel movement, time to mobilization, postoperative complications, and length of hospital stay were also compared between the two groups. RESULTS: Sixty-four patients (EA group, n = 33; MA group, n = 31) were analyzed. The patient characteristics did not differ markedly between the two groups. The frequency of additional analgesic use was significantly lower in the MA group than in the EA group (P < 0.001), whereas the VAS score did not differ markedly between the two groups. The postoperative blood pressure on the day of surgery was significantly lower in the MA group than in the EA group (P = 0.016), whereas urinary retention was significantly higher in the EA group than in the MA group (P < 0.001). CONCLUSION: MA combined with a single injection TAP block after laparoscopic colon cancer surgery may be comparable to EA in terms of analgesia and superior to EA in terms of urinary retention.

Targeting DNA methylation and B7-H3 in RB1-deficient and neuroendocrine prostate cancer.

Aberrant DNA methylation has been implicated as a key driver of prostate cancer lineage plasticity and histologic transformation to neuroendocrine prostate cancer (NEPC). DNA methyltransferases (DNMTs) are highly expressed, and global DNA methylation is dysregulated in NEPC. We identified that deletion of DNMT genes decreases expression of neuroendocrine lineage markers and substantially reduced NEPC tumor development and metastasis in vivo. Decitabine, a pan-DNMT inhibitor, attenuated tumor growth in NEPC patient-derived xenograft models, as well as retinoblastoma gene (RB1)-deficient castration-resistant prostate adenocarcinoma (CRPC) models compared with RB1-proficient CRPC. We further found that DNMT inhibition increased expression of B7 homolog 3 (B7-H3), an emerging druggable target, via demethylation of B7-H3. We tested DS-7300a (i-DXd), an antibody-drug conjugate targeting B7-H3, alone and in combination with decitabine in models of advanced prostate cancer. There was potent single-agent antitumor activity of DS-7300a in both CRPC and NEPC bearing high expression of B7-H3. In B7-H3-low models, combination therapy of decitabine plus DS-7300a resulted in enhanced response. DNMT inhibition may therefore be a promising therapeutic target for NEPC and RB1-deficient CRPC and may sensitize B7-H3-low prostate cancer to DS-7300a through increasing target expression. NEPC and RB1-deficient CRPC represent prostate cancer subgroups with poor prognosis, and the development of biomarker-driven therapeutic strategies for these populations may ultimately help improve patient outcomes.

Preoperative PI-RADS v2.1 Scoring System Improves Risk Classification in Patients Undergoing Radical Prostatectomy.

BACKGROUND/AIM: The purpose of this study was to examine the prognostic value of Prostate imaging-reporting and data system (PI-RADS) v2.1 scoring system in patients who underwent radical prostatectomy (RP). PATIENTS AND METHODS: Clinical data of 294 patients who received RP between 2006 and 2018 were reviewed and multiple parameters including PI-RADS v2.1 score were employed to identify predictive factors for biochemical recurrence (BCR). Tumor volume was calculated from prostatectomy specimens. RESULTS: Median age at operation and initial PSA level were 67 years old and 7.68 ng/ml, respectively. 44.9 and 24.8% of patients were diagnosed with PI-RADS score 4 and 5 prior to biopsies, respectively. BCR was observed in 17% of patients and median observation period was 63.43 months. After multivariate analysis, PI-RADS v2.1 score 5 [hazard ratio (HR)=2.24, p=0.0124] was an independent predictive factor of BCR in addition to clinical T stage (≥2c) (HR=2.32, p=0.0093) and biopsy Gleason score (≥8) (HR=2.81, p=0.0007). Furthermore, PI-RADS score 5 significantly stratified the prognosis in D'Amico intermediate- and high-risk groups (p=0.0174 and p=0.0013, respectively). We established novel risk classifications including PI-RADS v2.1 score and found that prognostic capabilities were improved as compared to the D'Amico classification. CONCLUSION: The PI-RADS v2.1 score exhibited significant prognostic value in patients with localized prostate cancer following RP. Risk classifications based on PI-RADS v2.1 score might provide better ability for predicting oncological outcomes as compared to the D'Amico classification system.

Clinical utility of the prognostic nutritional index in patients with metastatic hormone-sensitive prostate cancer: A retrospective, multicenter, cohort study.

BACKGROUND: The prognostic nutritional index (PNI) based on the serum albumin level and the lymphocyte count has been investigated as a prognostic factor in patients with malignant tumors. However, it has been poorly studied in prostate cancer (PCa), and little is known about its clinical utility. METHODS: Clinical data of 353 patients with de novo, metastatic, hormone-sensitive PCa (mHSPC) who received androgen deprivation therapy (ADT) were obtained from multiple institutions between 2000 and 2019. The impacts of the pretreatment PNI level on treatment response and survival, together with clinical parameters, were examined. The Mann-Whitney U test, Cox proportional hazards models, and Kaplan-Meier methods were used to evaluate significance. RESULTS: The median age and initial prostate-specific antigen level were 73 and 266.18 ng/mL, respectively. Patients with a low PNI had shorter progression-free survival (PFS), cancer-specific survival (CSS), and overall survival (OS) (p < 0.0001). On multivariate analysis, low PNI was an independent prognostic factor for OS (p = 0.0027, HR = 1.65), as well as advanced age (p = 0.049, HR = 1.38), the International Society of Urological Pathology (ISUP) grade group (GG) 5 (p = 0.0027, HR = 1.69), and elevated lactate dehydrogenase (LDH) (p < 0.0001, HR = 2.08). A propensity score-matching analysis showed that the PNI level remained a significant prognostic biomarker for PFS (p = 0.0263), CSS (p = 0.0006), and OS (p = 0.0015). Furthermore, a novel risk classification using PNI, LDH, and the ISUP GG was established to stratify patients' prognosis. An increase in the number of risk factors was significantly correlated with poor outcomes. CONCLUSIONS: A low pretreatment PNI might be an effective biomarker of poor treatment response and survival in patients with mHSPC undergoing ADT.

Tumor localization by Prostate Imaging and Reporting and Data System (PI-RADS) version 2.1 predicts prognosis of prostate cancer after radical prostatectomy.

An improved reading agreement rate has been reported in version 2.1 (v2.1) of the Prostate Imaging and Reporting and Data System (PI-RADS) compared with earlier versions. To determine the predictive efficacy of bi-parametric MRI (bp-MRI) for biochemical recurrence (BCR), our study assessed PI-RADS v2.1 score and tumor location in Japanese prostate cancer patients who underwent radical prostatectomy. Retrospective analysis was performed on the clinical data of 299 patients who underwent radical prostatectomy at Chiba University Hospital between 2006 and 2018. The median prostate-specific antigen (PSA) level before surgery was 7.6 ng/mL. Preoperative PI-RADS v2.1 categories were 1-2, 3, 4, and 5 in 35, 56, 138, and 70 patients, respectively. Tumor location on preoperative MRI was 107 in the transition zone (TZ) and 192 in the peripheral zone (PZ). BCR-free survival was significantly shorter in the PZ group (p = 0.001). In the total prostatectomy specimens, preoperative PI-RADS category 5, radiological tumor location, pathological seminal vesicle invasion, and Grade Group ≥ 3 were independent prognostic factors of BCR. These four risk factors have significant potential to stratify patients and predict prognosis. Radiological tumor location and PI-RADS v2.1 category using bp-MRI may enable prediction of BCR following radical prostatectomy.

Significance of RB Loss in Unlocking Phenotypic Plasticity in Advanced Cancers.

Cancer cells can undergo plasticity in response to environmental stimuli or under selective therapeutic pressures that result in changes in phenotype. This complex phenomenon of phenotypic plasticity is now recognized as a hallmark of cancer. Lineage plasticity is often associated with loss of dependence on the original oncogenic driver and is facilitated, in part, by underlying genomic and epigenetic alterations. Understanding the molecular drivers of cancer plasticity is critical for the development of novel therapeutic strategies. The retinoblastoma gene RB1 (encoding RB) is the first tumor suppressor gene to be discovered and has a well-described role in cell-cycle regulation. RB is also involved in diverse cellular functions beyond cell cycle including differentiation. Here, we describe the emerging role of RB loss in unlocking cancer phenotypic plasticity and driving therapy resistance across cancer types. We highlight parallels in cancer with the noncanonical role of RB that is critical for normal development and lineage specification, and the downstream consequences of RB loss including epigenetic reprogramming and chromatin reorganization that can lead to changes in lineage program. Finally, we discuss potential therapeutic approaches geared toward RB loss cancers undergoing lineage reprogramming.

Landscape of prostate-specific membrane antigen heterogeneity and regulation in AR-positive and AR-negative metastatic prostate cancer.

Tumor expression of prostate-specific membrane antigen (PSMA) is lost in 15-20% of men with castration-resistant prostate cancer (CRPC), yet the underlying mechanisms remain poorly defined. In androgen receptor (AR)-positive CRPC, we observed lower PSMA expression in liver lesions versus other sites, suggesting a role of the microenvironment in modulating PSMA. PSMA suppression was associated with promoter histone 3 lysine 27 methylation and higher levels of neutral amino acid transporters, correlating with 18F-fluciclovine uptake on positron emission tomography imaging. While PSMA is regulated by AR, we identified a subset of AR-negative CRPC with high PSMA. HOXB13 and AR co-occupancy at the PSMA enhancer and knockout models point to HOXB13 as an upstream regulator of PSMA in AR-positive and AR-negative prostate cancer. These data demonstrate how PSMA expression is differentially regulated across metastatic lesions and in the context of the AR, which may inform selection for PSMA-targeted therapies and development of complementary biomarkers.

Detection of intraductal carcinoma in prostate cancer patients with small tumor volume.

OBJECTIVES: The purpose of this study was to investigate intraductal carcinoma of the prostate (intraductal carcinoma) and significant cancer (SC) in patients with small tumor volume (<0.5 cm3 ) in prostatectomy specimens. METHODS: Data from 639 patients undergoing radical prostatectomy between April 2006 and December 2017 at Chiba University Hospital and 2 affiliated institutions were retrospectively reviewed. Tumor volume in prostatectomy specimens was measured, and with a tumor volume of less than 0.5 cm3 , the presence of intraductal carcinoma and SC was examined. SC was defined as one that did not meet the definition of pathological insignificant cancer (organ-confined cancer, Grade Group 1, tumor volume < 0.5 cm3 ). The number of patients who met four active surveillance (AS) protocols was also examined. RESULTS: A total of 83 patients with tumor volume < 0.5 cm3 were identified in this study population (SC: 43 patients [52%], intraductal carcinoma: 5 patients [6%]). The median follow-up was 34.6 months (range: 18-57 months). Four (5%) developed biochemical recurrence. The number of positive biopsy cores ≥ 2 was an independent predictor of SC in patients with tumor volume < 0.5 cm3 (hazard ratio: 4.39; 95% confidence interval: 1.67-11.56; p = 0.003). In tumor volume < 0.5 cm3 , tumor volume was significantly correlated with the International Society of Urological Pathology Grade Group (1 vs. 4-5, p = 0.002) and the presence of intraductal carcinoma (p = 0.004). In intraductal carcinoma-positive cases, four of five patients (80%) had the predictor of SC, which was two or more positive biopsy cores. Of the four AS protocols, the criteria for Prostate Cancer Research International: Active Surveillance were met most frequently in 46 cases (55%) of tumor volume less than 0.5 cm3 if targeted biopsy by magnetic resonance imaging was available. CONCLUSION: The results of the present study suggest that intraductal carcinoma was present even in cases with small tumor volumes. Grade Group and intraductal carcinoma showed a positive correlation with tumor volume.

Progression of Recurrent Pancreatitis to Chronic Pancreatitis within 3 Years due to SPINK1 Mutation IVS3+2T>C.

When the etiology of pancreatitis cannot be determined despite sufficient investigation, recurrence and progression to chronic pancreatitis often involve genetic mutations. Herein, we describe a case of recurrent pancreatitis with the IVS3+2T>C mutation in the serine protease inhibitor Kazal type 1 (SPINK1) gene that progressed to chronic pancreatitis in only 3 years. A 35-year-old man was referred to our hospital, where he was diagnosed with mild pancreatitis and was treated conservatively. However, the patient experienced recurrent episodes of pancreatitis, which progressed to become chronic pancreatitis with a pancreatic calcification 1 year later. After 3 years, the patient developed pancreatic duct stenosis and required a pancreatic duct stent placement. Regarding the cause of chronic pancreatitis, alcohol abuse was ruled out based on history taking. Considering the course of treatment, autoimmune pancreatitis and obstructive pancreatitis, such as pancreatic divisum, were also ruled out. Finally, a germline genetic test was performed to determine the etiology of pancreatitis, which revealed the IVS3+2T>C mutation in SPINK1. This case shows the importance of genetic testing in patients with idiopathic pancreatitis to determine their etiology and is a rare incident that can report the progression of the disease from acute to chronic pancreatitis.

Integrated analysis of tertiary lymphoid structures in relation to tumor-infiltrating lymphocytes and patient survival in pancreatic ductal adenocarcinoma.

BACKGROUND: Tertiary lymphoid structure (TLS) reflects an intense immune response against cancer, which correlates with favorable patient survival. However, the association of TLS with tumor-infiltrating lymphocytes (TILs) and clinical outcomes has not been investigated comprehensively in pancreatic ductal adenocarcinoma (PDAC). METHODS: We utilized an integrative molecular pathological epidemiology database on 162 cases with resected PDAC, and examined TLS in relation to levels of TILs, patient survival, and treatment response. In whole-section slides, we assessed the formation of TLS and conducted immunohistochemistry for tumor-infiltrating T cells (CD4, CD8, CD45RO, and FOXP3). As confounding factors, we assessed alterations of four main driver genes (KRAS, TP53, CDKN2A [p16], and SMAD4) using next-generation sequencing and immunohistochemistry, and tumor CD274 (PD-L1) expression assessed by immunohistochemistry. RESULTS: TLSs were found in 112 patients with PDAC (69.1%). TLS was associated with high levels of CD4+ TILs (multivariable odds ratio [OR], 3.50; 95% confidence interval [CI] 1.65-7.80; P = 0.0002), CD8+ TILs (multivariable OR, 11.0; 95% CI 4.57-29.7, P < 0.0001) and CD45RO+ TILs (multivariable OR, 2.65; 95% CI 1.25-5.80, P = 0.01), but not with levels of FOXP3+ TILs. TLS was associated with longer pancreatic cancer-specific survival (multivariable hazard ratio, 0.37; 95% CI 0.25-0.56, P < 0.0001) and favorable outcomes of adjuvant S-1-treatment. TLS was not associated with driver gene alterations but tumor CD274 negative expression. CONCLUSIONS: Our comprehensive data supports the surrogacy of TLS for vigorous anti-tumor immune response characterized by high levels of helper and cytotoxic T cells and their prognostic role.