PD-L1 expression as a prognostic marker in patients with advanced biliary tract cancer.

2020 ◽  
Vol 38 (15_suppl) ◽  
pp. e16679-e16679
Author(s):  
Hyera Kim ◽  
Jung Yong Hong ◽  
Jeeyun Lee ◽  
Se Hoon Park ◽  
Joon Oh Park ◽  
...  
Keyword(s):  
Biliary Tract ◽  
Biliary Tract Cancer ◽  
Checkpoint Inhibitors ◽  
Univariate Analysis ◽  
Group Analysis ◽  
Progression Free Survival ◽  
Tumor Location ◽  
Tract Cancer ◽  
Positive Score ◽  
Combined Positive Score

e16679 Background: Biliary tract cancer (BTC) is associated with poor prognosis because of its aggressive and heterogeneous nature. Programmed death ligand 1 (PD-L1) has been considered as a novel biomarker for prognosis and response of immune checkpoint inhibitors in various tumors. However, there are limited data reporting on the role of PD-L1 in advanced BTC patients. Methods: We analyzed 186 patients with advanced BTC who received palliative gemcitabine and platinum between May 2010 and December 2019. All patients were evaluated for PD-L1 expression by combined positive score (CPS) positivity. Results: In all 186 patients, the median age was 62 years (range 38-82), and the primary tumor location was intrahepatic cholangiocarcinoma (IH-CCC) in 72 patients (38.7%), extrahepatic (EH)-CCC in 90 (48.4%), and gallbladder (GB) cancer in 24 (12.9%). There were 158 (84.9%) patients with recurrent disease and 28 (15.1%) with metastatic disease. Among the 186 patients, 53 (28.5%) had PD-L1 CPS positivity, and 133 were CPS negative. The median overall survival (OS) of patients with PD-L1 CPS positivity or negativity was 12.1 and 15.4 months, respectively. The median progression-free survival (PFS) in patients with PD-L1 positivity or negativity was 5.7 and 7.1 months, respectively. The OS and PFS were not statistically different between groups. In sub-group analysis, EH-CCC patients with PD-L1 negativity had more favorable OS (17.2 vs. 11.6 months, p= 0.002) and PFS (7.8 vs. 5.4 months, p= 0.005) than those that were PD-L1 negative. However, this finding was not reproduced in patients with IH-CCC or GB cancer. Univariate analysis of the association between PD-L1 expression and OS in patients with advanced BTC indicated that PD-L1 CPS positivity has a prognostic role in sub-populations older than 60 years (HR 1.743, CI 1.001-3.034, p = 0.050), those with EH-CCC (HR 2.449, CI 1.355-4.426, p = 0.003), and those with liver metastasis (HR 2.511, CI 1.362-4.626, p = 0.003). Conclusions: This study demonstrated that PD-L1 expression might be a novel prognostic biomarker in patients with EH-CCC but not for patients with IH-CCC or GB cancer.

Programmed Death Ligand 1 Expression as a Prognostic Marker in Patients with Advanced Biliary Tract Cancer

Oncology ◽  
2021 ◽  
pp. 1-8
Author(s):  
Hyera Kim ◽  
Jinchul Kim ◽  
Seonggyu Byeon ◽  
Kee-Taek Jang ◽  
Jung Yong Hong ◽  
...  
Keyword(s):  
Biliary Tract ◽  
Biliary Tract Cancer ◽  
Checkpoint Inhibitors ◽  
Progression Free Survival ◽  
Tumor Location ◽  
Extrahepatic Cholangiocarcinoma ◽  
Programmed Death Ligand 1 ◽  
Tract Cancer ◽  
Programmed Death ◽  
Combined Positive Score

Background: Biliary tract cancer (BTC) is associated with poor prognosis because of its aggressive and heterogeneous nature. Programmed death ligand 1 (PD-L1) has been considered a novel biomarker for prognosis and response of immune checkpoint inhibitors in various tumors. However, there are limited data reporting on the role of PD-L1 in advanced BTC patients. Patients and Methods: We analyzed 186 patients with advanced BTC who received palliative gemcitabine and platinum between May 2010 and December 2019. All patients were evaluated for PD-L1 expression by combined positive score positivity. Results: Of the 186 patients, the primary tumor location was intrahepatic cholangiocarcinoma (IHCC) in 72 (38.7%), extrahepatic cholangiocarcinoma (EHCC) in 90 (48.4%), and gallbladder (GB) cancer in 24 (12.9%). Among all the patients, 53 (28.5%) had PD-L1 positivity. The median overall survival (OS) of patients with PD-L1 positivity or negativity was 12.1 and 15.4 months, respectively. The median progression-free survival (PFS) in patients with PD-L1 positivity or negativity was 5.7 and 7.1 months, respectively. OS and PFS were not statistically different between groups. In subgroup analysis, EHCC patients with PD-L1 negativity had more favorable OS (17.2 vs. 11.6 months, p = 0.002) and PFS (7.8 vs. 5.4 months, p = 0.005) than those who were PD-L1-positive. However, this finding was not reproduced in patients with IHCC or GB cancer. Conclusion: This study demonstrated that PD-L1 expression might be a novel prognostic biomarker in patients with EHCC but not in patients with IHCC or GB cancer.

Efficacy and safety of nivolumab in first-line or further treatment of advanced metastatic biliary tract cancer.

2019 ◽  
Vol 37 (4_suppl) ◽  
pp. 315-315
Author(s):  
Miaomiao Gou ◽  
Yong Zhang ◽  
Haiyan Si ◽  
Guanghai Dai
Keyword(s):  
Biliary Tract ◽  
Biliary Tract Cancer ◽  
Univariate Analysis ◽  
Objective Response ◽  
Progression Free Survival ◽  
Complete Response ◽  
Hematologic Toxicity ◽  
Efficacy And Safety ◽  
Peripheral Neurotoxicity ◽  
Tract Cancer

315 Background: PD-1 inhibitors have improved efficacy in many cancers. There are few report of nivolumab for metastatic biliary tract cancer (MBTC). This study reviewed the efficacy and safety of nivolumab for MBTC to improve efficacy and survival. Methods: Thirty patients with MBTC were voluntarily treated with non-clinical nivolumab at the PLA General Hospital. Nivolumab 200 mg or 180 mg was administered according to patient tolerance. Progression free survival (PFS), overall survival (OS) was evaluated by kaplan-meier and univariate analysis were carried out among clinical characteristics. Objective response rates (ORR), disease control rates (DCR), and treatment-related adverse events (AEs) were also evaluated. Results: The median treatment cycle is 4 cycles. One case was complete response (CR), 5 cases partial response (PR), 12 cases stable (SD). ORR was 20%, DCR was 60%. PFS was 3.1m (95% CI: 2.13~4.06 months). The AEs of nivolumab monothrapy were fatigue (3 cases), fever (2 cases), hypothyroidism (1 case), skin reaction (1 case). Nivolumab combined with chemotherapy related 1-2 hematologic toxicity were leukopenia (5 cases), thrombocytopenia (2 cases), and grade 3-4 were leukopenia (3 cases). Non-hematologic toxicity grade 1-2 were nausea and vomiting (4 cases), fatigue (4 cases), fever (3 cases), peripheral neurotoxicity (3 cases), and hypothyroidism (1 case). Univariate analysis showed that PFS was 4.20m in patients older than 53 years, slightly higher than those younger than 53 years (3.0 m, P = 0.047). PFS of nivolumab combined with chemotherapy was statistically significant compared with nivolumab monothrapy (4.1 m vs 2.3 m, p = 0.031). Patients with metastatic number > 2 had a shorter PFS than those < 2 (1.4 m vs 4.1 m, P = 0.05). PD-L1 expression positive have no better PFS compared with PD-L1 negative (3.6 m vs 3.1 m , p = 0.801). Multivariate analysis show nivolumab combined with chemotherapy was only independent factor for longer PFS (HR: 0.432, P < 0.05). Conclusions: the safety of nivolumab in MBTC is controllable. Subgroup analysis suggests that further selection of superior populations is needed and sample size need to be expanded to improve the efficacy of nivolumab in MBTC.

scholarly journals Efficacy and Safety of Pembrolizumab for Gemcitabine/Cisplatin-Refractory Biliary Tract Cancer: A Multicenter Retrospective Study

2020 ◽  
Vol 9 (6) ◽  
pp. 1769 ◽  
Author(s):  
Sang Hoon Lee ◽  
Hee Seung Lee ◽  
Sang Hyub Lee ◽  
Sang Myung Woo ◽  
Dong Uk Kim ◽  
...  
Keyword(s):  
Cell Death ◽  
Programmed Cell Death ◽  
Biliary Tract ◽  
Biliary Tract Cancer ◽  
Progression Free Survival ◽  
Cancer Type ◽  
Extrahepatic Cholangiocarcinoma ◽  
Tract Cancer ◽  
Tertiary Hospitals ◽  
Melanoma Treatment

Pembrolizumab, an anti-programmed cell death (PD)-1 monoclonal antibody, is an anticancer agent showing substantial benefit in lung cancer and melanoma treatment. Biliary tract cancer (BTC) has been shown to respond to pembrolizumab; however, no credible data of such treatment outcomes exist. Therefore, we assessed the clinical outcomes and safety of pembrolizumab in patients with gemcitabine/cisplatin-refractory BTC. In this multicenter study, we retrospectively analyzed 51 patients with programmed cell death 1-ligand 1 (PD-L1)-positive gemcitabine/cisplatin-refractory BTC treated with pembrolizumab in four tertiary hospitals in Korea. PD-L1 positivity was defined as the expression of PD-L1 in ≥1% of tumor cells based on immunohistochemical staining (22C3, SP263, and E1L3N assays). The median age of the patients was 66 (range, 43–83) years and 29 (56.9%) were male. Extrahepatic cholangiocarcinoma was the most common cancer type (n = 30, 58.8%). Partial response and stable disease were achieved in 5 (9.8%) and 13 (25.5%) patients, respectively. Median progression-free survival and overall survival were 2.1 (95% CI, 1.7–2.4) and 6.9 (95% CI, 5.4–8.3) months, respectively. Overall, 30 (58.8%) patients experienced treatment-related adverse events (AEs). Only four (7.8%) patients experienced grades 3 and 4 AEs. In PD-L1-positive gemcitabine/cisplatin-refractory BTC, pembrolizumab presented durable efficacy, with a 9.8% response rate and manageable toxicity.

Prognostic factors in advanced biliary tract cancer treated with first-line chemotherapy with cisplatin and gemcitabine.

2014 ◽  
Vol 32 (3_suppl) ◽  
pp. 350-350
Author(s):  
Renata D'Alpino Peixoto ◽  
Daniel John Renouf ◽  
Howard John Lim
Keyword(s):  
Prognostic Factors ◽  
Biliary Tract ◽  
Biliary Tract Cancer ◽  
Primary Tumor ◽  
Advanced Disease ◽  
Tumor Location ◽  
Primary Tumor Location ◽  
Tract Cancer ◽  
Ecog Ps ◽  
Line Chemotherapy

350 Background: Data regarding prognostic factors in advanced biliary tract cancer (ABTC) remains scarce. The aim of this study was to review our experience in ABTC as well as to evaluate potential prognostic factors for overall survival (OS) as defined in the ABC-02 trial. Methods: 106 consecutive patients with ABTC who initiated palliative chemotherapy with Cisplatin and Gemcitabine from 2009 to 2012 at the BC Cancer Agency were identified using our pharmacy database. Clinicopathologic variables and treatment outcome were retrospectively collected. Potential prognostic factors were assessed by univariate (Kaplan-Meier curves and log-rank test) and multivariate analyses (Cox proportional hazards model). Results: 106 patients (46 males) with a median age of 64 years (range 43 – 88) were included. Median progression free-survival (PFS) was 6.2 months (95%CI: 5.4-7.0). Median OS from diagnosis of advanced disease to death was 12.9 months (95%CI: 10.0-15.7), while median OS from initiation of chemotherapy to death was 10.0 months (95%CI: 7.3-12.6). 34.9% of the patients received 2nd line chemotherapy, with single-agent 5-fluorouracil being the most used drug. On univariate analysis, ECOG performance status (PS) at diagnosis, primary tumor location (gallbladder, intra-hepatic cholangiocarcinoma, extra-hepatic cholangiocarcinoma, ampulla of Vater, unkown), and sites of advanced disease (unresectable locally advanced, regional lymph nodes, liver-limited metastases, extra-hepatic metastases) were significantly associated with worse OS (p < 0.001, 0.003 and 0.009, respectively). Age, gender, CA19-9, CEA, hemoglobin, neutrophil count, prior stent and prior surgery were not significantly associated with OS. On multivariate analysis, predictors of poorer OS were ECOG PS (p<0.001), primary location (p=0.009), site of advanced disease (p=0.006) and CEA (p=0.002). Conclusions: In this population based analysis, outcomes for patients with ABTC were comparable to those noted in the ABC-02 trial. ECOG PS, primary tumor location, site of advanced disease and CEA were all found to be significantly prognostic.

Clinical benefit of maintenance therapy for patients with advanced biliary tract cancer without progression on first-line gemcitabine plus cisplatin.

2018 ◽  
Vol 36 (4_suppl) ◽  
pp. 357-357
Author(s):  
Jaewon Hyung ◽  
Changhoon Yoo ◽  
Kyu-Pyo Kim ◽  
Bum Jun Kim ◽  
Jae Ho Jeong ◽  
...  
Keyword(s):  
Maintenance Therapy ◽  
Biliary Tract ◽  
Biliary Tract Cancer ◽  
Clinical Benefit ◽  
Medical Center ◽  
Progression Free Survival ◽  
Observation Group ◽  
First Line ◽  
Tract Cancer ◽  
Maintenance Group

357 Background: Gemcitabine plus cisplatin (GP) is the standard first line chemotherapy for patients with advanced biliary tract cancer (BTC). In the pivotal ABC-02 study, patients received up to 24 weeks (6-8 cycles) of three-weekly GP. In daily practice setting, however, patients without progression often receive GP more than 6-8 cycles. It is uncertain whether maintenance treatment has clinical benefit in patients without progression on GP. Methods: Advanced BTC patients treated with GP between April 2010 and February 2015 in Asan Medical Center, Seoul, Korea, were retrospectively analyzed. Among the patients who did not progressed and stopped GP after 6-8 cycles, patients were stratified according to the further treatment; those with or without further cycles of GP (maintenance group vs observation group). Primary endpoint was overall survival (OS). Results: Among 740 patients, 231 patients (31.2%) were eligible for this analysis; 111 for observation group, 120 for maintenance group. In observation group, 76 patients (68.5%) stopped GP due to completion of scheduled chemotherapy and 27 patients (24.3%) due to the patients’ request or toxicity. There were no statistically significant differences in baseline characteristics between two groups. Median OS from the initiation of GP was 20.5 months [95% CI 15.4-25.6] and 22.4 months [95% CI 17.0-27.8] in the observation and maintenance group, respectively (p = 0.32). Median progression-free survival (PFS) was 10.4 months [95% CI 7.0-13.8] and 13.2 months [95% CI 11.3-15.2], respectively (p = 0.22). These were consistent in the multivariate analyses for OS and PFS after the adjustment of prognostic factors. Conclusions: In our analysis, maintenance therapy of GP was not associated with improved survival outcomes. Considering the potential disadvantages such as cumulative toxicities, maintenance therapy may not be beneficial in patients who did not progressed on 6-8 cycles of GP.

scholarly journals Genomic alterations in biliary tract cancer predict prognosis and immunotherapy outcomes

2021 ◽  
Vol 9 (11) ◽  
pp. e003214
Author(s):  
Xiaofeng Chen ◽  
Deqiang Wang ◽  
Jing Liu ◽  
Jingrong Qiu ◽  
Jun Zhou ◽  
...  
Keyword(s):  
Biliary Tract ◽  
Biliary Tract Cancer ◽  
Poor Prognosis ◽  
Immune Cell ◽  
Checkpoint Inhibitors ◽  
Early Stage ◽  
Chinese Patients ◽  
Genomic Alterations ◽  
Early Stage Disease ◽  
Tract Cancer

BackgroundRecently, immunotherapy with immune checkpoint inhibitors (ICIs) has shown promising efficacy in biliary tract cancer (BTC), which includes gallbladder cancer (GBC) and cholangiocarcinoma (CHOL). Understanding the association between immunotherapy outcomes and the genomic profile of advanced BTC may further improve the clinical benefits from immunotherapy.MethodsGenomic tumor DNA was isolated from 98 Chinese patients with advanced BTC and used for targeted next-generation sequencing of 416 cancer-related genes to identify the genomic alterations common to advanced BTC. Thirty-four patients had received ICI camrelizumab plus gemcitabine and oxaliplatin (from the NCT03486678 trial) as a first-line treatment. Tumor-infiltrating immune cells were evaluated using immunofluorescence staining.ResultsKRAS and TP53 mutations were much more frequent in the advanced-stage BTC cohort than in other cohorts with mostly early stage disease. Specifically, KRAS-TP53 co-mutations were favored in advanced CHOL, with a favorable response to immunotherapy, while single KRAS mutations predicted poor prognosis and immunotherapy outcomes for CHOL. Compared with GBC, CHOL had more mutations in genes involved in KRAS signaling; a high mutation load in these genes correlated with poor immunotherapy outcomes and may subsequently cause inferior immunotherapy outcomes for CHOL relative to GBC. Furthermore, a genomic signature including 11 genes was developed; their mutated subtype was associated with poor prognosis and immunotherapy outcomes in both CHOL and GBC. Transcriptome analyses suggested immune dysfunction in the signature mutated subtype, which was validated by tumor microenvironment (TME) evaluation based on detection of immune cell infiltration. Importantly, the signature wild-type subtype with favorable TME may be an advantageous population of immunotherapy.ConclusionsGenomic alterations in advanced BTC were associated with specific prognosis and immunotherapy outcomes. Combining genomic classification with TME evaluation further improved the stratification of immunotherapy outcomes.

scholarly journals Tumor Mutational Burden as a Biomarker for Advanced Biliary Tract Cancer

2021 ◽  
Vol 20 ◽  
pp. 153303382110623
Author(s):  
Hongsik Kim ◽  
Hana Kim ◽  
Ryul Kim ◽  
Hyunji Jo ◽  
Hye Ryeon Kim ◽  
...  
Keyword(s):  
Biliary Tract ◽  
Biliary Tract Cancer ◽  
Objective Response ◽  
Progression Free Survival ◽  
Line Treatment ◽  
First Line ◽  
Tract Cancer ◽  
Mutational Burden ◽  
Tumor Mutational Burden ◽  
First Line Treatment

Background: High tumor mutational burden (TMB-H) has been reported as a predictive marker to immunotherapy or prognostic marker in various tumor types. However, there has been little study of the role of TMB-H in advanced biliary tract cancer (BTC). Methods: We analyzed 119 advanced BTC patients who received Gemcitabine/Cisplatin (GP) as a first-line treatment between November 2019 and April 2021. Next-generation sequencing (NGS), including TMB analysis, as a routine clinical practice was performed in 119 patients. The TruSightTM Oncology 500 assay from Illumina was used as a cancer panel. Results: Among 119 patients, 18 (18.5%) had a tumor with high TMB (≥ 10 Muts/Mb). There were no significant differences between the status of TMB and clinical outcomes with GP, including objective response rate (ORR) ( P = .126), disease control rate (DCR) ( p = .454), and median progression-free survival (PFS) ( p = .599). The median overall survival (OS) was not different between patients with TMB-H and no TMB-H ( p = .430). In subgroup analysis of 32 patients receiving immune checkpoint inhibitor (ICIs), there were significant differences in ORR ( p = .034) and median PFS ( p  = .025) with ICIs between patients with and without TMB-H. Conclusions: This study revealed that TMB-H in advanced BTCs did not have a prognostic or role in the standard first-line treatment. However, TMB-H might be a predictive biomarker for response to ICIs in advanced BTC.

scholarly journals Current Progress and Future Perspectives of Immune Checkpoint Inhibitors in Biliary Tract Cancer

2021 ◽  
Vol Volume 14 ◽  
pp. 1873-1882
Author(s):  
Poshita-Kumari Seesaha ◽  
Kang-Xin Wang ◽  
Guo-Qun Wang ◽  
Ting-Yun Cui ◽  
Feng-Jiao Zhao ◽  
...  
Keyword(s):  
Biliary Tract ◽  
Biliary Tract Cancer ◽  
Immune Checkpoint ◽  
Immune Checkpoint Inhibitors ◽  
Checkpoint Inhibitors ◽  
Future Perspectives ◽  
Tract Cancer

scholarly journals Efficacy and Safety of Pembrolizumab in Patients with Refractory Advanced Biliary Tract Cancer: Tumor Proportion Score as a Potential Biomarker for Response

2020 ◽  
Vol 52 (2) ◽  
pp. 594-603 ◽  
Author(s):  
Junho Kang ◽  
Jae Ho Jeong ◽  
Hee-Sang Hwang ◽  
Sang Soo Lee ◽  
Do Hyun Park ◽  
...  
Keyword(s):  
Biliary Tract ◽  
Biliary Tract Cancer ◽  
Objective Response ◽  
Evaluation Criteria ◽  
Progression Free Survival ◽  
Complete Response ◽  
Current Standard ◽  
Durable Response ◽  
Tract Cancer ◽  
Potential Biomarker

Purpose The current standard chemotherapy for advanced biliary tract cancer (BTC) has limited benefit, and novel therapies need to be investigated. Materials and MethodsIn this prospective cohort study, programmed death ligand-1 (PD-L1)–positive BTC patients who progressed on first-line gemcitabine plus cisplatin were enrolled. Pembrolizumab 200 mg was administered intravenously every 3 weeks. ResultsBetween May 2018 and February 2019, 40 patients were enrolled. Pembrolizumab was given as second-line (47.5%) or ≥ third-line therapy (52.5%). The objective response rate was 10% and 12.5% by Response Evaluation Criteria in Solid Tumor (RECIST) v1.1 and immune- modified RECIST (imRECIST) and median duration of response was 6.3 months. Among patients with progressive disease as best response, one patient (1/20, 5.0%) achieved complete response subsequently. The median progression-free survival (PFS) and overall survival (OS) were 1.5 months (95% confidence interval [CI], 0.0 to 3.0) and 4.3 months (95% CI, 3.5 to 5.1), respectively, and objective response per imRECIST was significantly associated with PFS (p < 0.001) and OS (p=0.001). Tumor proportion score ≥ 50% was significantly associated with higher response rates including the response after pseudoprogression (vs. < 50%; 37.5% vs. 6.5%; p=0.049). Conclusion Pembrolizumab showed modest anti-tumor activity in heavily pretreated PD-L1–positive BTC patients. In patients who showed objective response, durable response could be achieved.

scholarly journals Anti-PD-1 therapy combined with chemotherapy in patients with advanced biliary tract cancer

2019 ◽  
Vol 68 (9) ◽  
pp. 1527-1535 ◽  
Author(s):  
Danyang Sun ◽  
Junxun Ma ◽  
Jinliang Wang ◽  
Chun Han ◽  
Yuanyu Qian ◽  
...  
Keyword(s):  
Biliary Tract ◽  
Biliary Tract Cancer ◽  
Primary Outcome ◽  
Progression Free Survival ◽  
Immune Checkpoints ◽  
Combination Group ◽  
Free Survival ◽  
Tract Cancer ◽  
Previously Treated ◽  
Grade 3

Abstract Background Evidence for the efficacy of immunotherapy in biliary tract cancer (BTC) is limited and unsatisfactory. Methods Chinese BTC patients receiving a PD-1 inhibitor with chemotherapy, PD-1 inhibitor monotherapy or chemotherapy alone were retrospectively analyzed. The primary outcome was overall survival (OS). The key secondary outcomes were progression-free survival (PFS) and safety. Patients previously treated with any agent targeting T cell costimulation or immune checkpoints were excluded. Results The study included 77 patients (a PD-1 inhibitor plus chemotherapy, n = 38; PD-1 inhibitor monotherapy, n = 20; chemotherapy alone, n = 19). The median OS was 14.9 months with a PD-1 inhibitor plus chemotherapy, significantly longer than the 4.1 months with PD-1 inhibitor monotherapy (HR 0.37, 95% CI 0.17–0.80, P = 0.001) and the 6.0 months with chemotherapy alone (HR 0.63, 95% CI 0.42–0.94, P = 0.011). The median PFS was 5.1 months with a PD-1 inhibitor plus chemotherapy, significantly longer than the 2.2 months with PD-1 inhibitor monotherapy (HR 0.59, 95% CI 0.31–1.10, P = 0.014) and the 2.4 months with chemotherapy alone (HR 0.61, 95% CI 0.45–0.83, P = 0.003). Grade 3 or 4 treatment-related adverse events were similar between the anti-PD-1 combination group and the chemotherapy alone group (34.2% and 36.8%, respectively). Conclusions Anti-PD-1 therapy plus chemotherapy is an effective and tolerable approach for advanced BTC.

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