Comprehensive characterization of cell-free tumor DNA in plasma and urine of patients with renal tumors

BACKGROUND

Cell-free tumor-derived DNA (ctDNA) allows non-invasive monitoring of cancers, but its utility in renal cell cancer (RCC) has not been established.

METHODS

Here, a combination of untargeted and targeted sequencing methods, applied to two independent cohorts of patients (n = 91) with various renal tumor subtypes, were used to determine ctDNA content in plasma and urine.

RESULTS

Our data revealed lower plasma ctDNA levels in RCC relative to other cancers of similar size and stage, with untargeted detection in 27.5% of patients from both cohorts. A sensitive personalized approach, applied to plasma and urine from select patients (n = 22) improved detection to ~ 50%, including in patients with early-stage disease and even benign lesions. Detection in plasma, but not urine, was more frequent amongst patients with larger tumors and in those patients with venous tumor thrombus. With data from one extensively characterized patient, we observed that plasma and, for the first time, urine ctDNA may better represent tumor heterogeneity than a single tissue biopsy. Furthermore, in a subset of patients (n = 16), longitudinal sampling revealed that ctDNA can track disease course and may pre-empt radiological identification of minimal residual disease or disease progression on systemic therapy. Additional datasets will be required to validate these findings.

CONCLUSIONS

These data highlight RCC as a ctDNA-low malignancy. The biological reasons for this are yet to be determined. Nonetheless, our findings indicate potential clinical utility in the management of patients with renal tumors, provided improvement in isolation and detection approaches.

Abstract 1367: Comprehensive characterization of cell-free tumor DNA in plasma and urine of patients with renal tumors

Renal cell carcinoma (RCC) represents a heterogenous disease in terms of histologic subtypes, prognosis and treatment response. Genetic heterogeneity offers a particular challenge to direct available targeted therapies that best match the patient. Profiling and monitoring of tumor-specific alterations from body fluids has been demonstrated as a valuable tool for many tumor types. Yet, the utility of circulating tumor DNA (ctDNA) in RCC has not been well established. To characterize the levels and composition of ctDNA in the plasma and urine we employed a broad range of targeted and untargeted methods to two independent cohorts of patients with renal tumors. We applied shallow Whole Genome Sequencing (sWGS) and modified Fast Aneuploidy Screen Test-Sequencing System (mFAST-SeqS) to 43 patients with metastatic RCCs. Using the mFAST-SeqS, ctDNA was detectable in only 2 out of 43 patients (4.7%). However, assessment of tumor fractions based on sWGS using the ichorCNA algorithm revealed 6 further patients with detectable amounts of ctDNA. In silico size selection of fragments < 150bp further improved the detection rate to 27% (12 out of 43 patients). This is consistent with previous reports that tumor-derived fragments are often smaller compared to cell-free DNA of normal cells and as such enrichment of smaller fragment increases the sensitivity. High-resolution mutation analysis of 10 recurrently mutated genes in RCC was performed using a QIASeq custom capture panel, enabling detection of tumor-specific mutations at baseline in 18% (8/43) of patients. Of these five had detectable tumor fractions as observed with ichorCNA. Furthermore, we had access to longitudinally obtained plasma samples for 37 of our 43 (86%) patients with a median follow-up period of 6 months (range, 0.4-19.2). The QIASeq panel was applied to follow-up patients of which mutations were identified at baseline. For most of these patients, ctDNA was elevated at treatment initiation but decreased with response. At the time of progression, or when a response could not be achieved, ctDNA increased or remained elevated. Plasma and urine samples were available for a second cohort (n=47) of patients with a wide range of renal tumors. Detection rates using both broad, untargeted sequencing methods and targeted, sensitive approaches were similarly low with 7/47 (14.9%) and 45.5% (10/22), respectively. Interrogation of those patients with detectable ctDNA revealed, for the first time, that urine ctDNA is capable of overcoming genetic heterogeneity and offers information that is complementary to that provided by plasma. Taken together, our data revealed that ctDNA levels are lower in RCC than other cancers of similar stage. Although, ctDNA can be detected in blood and urine of RCC patients and there is potential for clinical utility, improved isolation and detection methods are needed to achieve a broad patient coverage.

Citation Format: Tina Moser, Christopher G. Smith, Maximilian Seles, Gabriel Wcislo, Matthew Eldridge, Samantha Perakis, Florent Mouliere, Isaac Lazzeri, Katrin Heider, Anne Warren, Nitzan Rosenfeld, Grant D. Stewart, Ellen Heitzer. Comprehensive characterization of cell-free tumor DNA in plasma and urine of patients with renal tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 1367.

Serum TRAIL levels in patients with epithelial ovarian cancer or primary peritoneal cancer treated with neoadjuvant chemotherapy. A pilot study

AIMS

The study attempted to evaluate the kinetics of changes in serum TRAIL levels as a potential predictive and prognostic factor in patients with epithelial ovarian cancer (EOC) or primary peritoneal carcinoma (PPC), eligible for an interval debulking surgery (IDS).

MATERIAL AND METHODS

17 patients with primary inoperable EOC or PPC in FIGO Stage IIIC or IV who underwent an exploratory operation were enrolled to the study. Serum TRAIL levels were determined by ELISA method (DIACLONE, Besancon Cedex, France) before and after two courses of neoadjuvant chemotherapy (NAC) based on paclitaxel and platinum analogue (cisplatin or carboplatin). The control group consisted of six healthy volunteers. The median difference in concentration of TRAIL (dTRAIL) between the initial marking and after two courses of NAC in each patient was 192 pg/ml and it was used for dichotomization of the test group.

RESULTS

Suboptimal interval debulking surgery (IDS) was performed in 23.5% (4/17) and optimal IDS in 76.5% (13/17) patients. TRAIL concentration before chemotherapy did not differ significantly between patients with EOC or PPC [1426.96 +/- 321.06 pg/ml (mean +/- SD) (U = 26, p = 0.08)] and the control group [1160.40 +/- 256.39 pg/ml (mean +/- SD. After two courses of NAC serum TRAIL concentration level was 1247.49 +/- 378.46 pg/ml (mean +/- SD). The difference was significant (Z = 2.44, p = 0.0147). Statistical analysis showed that dTRAIL did not significantly influence either extent of IDS (U = 35, p = 0.0962) or time to progression (log-rank test, p = 0.1185), overall survival (log-rank test, p = 0.1973) and response to treatment according to RECIST criteria (U = 35.5, p = 0.9616).

CONCLUSIONS

Serum TRAIL concentration levels changed significantly during NAC. However, it seems that the concentration of this protein has no critical value as a predictive or prognostic factor in patients with EOC or PPC.

The role of erythropoietin and its receptor in growth, survival and therapeutic response of human tumor cells From clinic to bench - a critical review

Recombinant human erythropoietin (rhEPO) has been used clinically to alleviate cancer- and chemotherapy-related anemia. However, recent clinical trials have reported that rhEPO also may adversely impact disease progression and survival. The expression of functional EPO receptors (EPOR) has been demonstrated in many human cancer cells where, at least in vitro, rhEPO can stimulate cell growth and survival and may induce resistance to selected therapies. Responses to rhEPO measured by alterations in tumor cell growth or survival, activation of signaling pathways or modulation of sensitivity to anticancer agents are variable. Both methodological and inherent biological issues underlie the differential cell responses, including reported difficulties in EPOR protein detection, potential involvement of EPOR isoforms or of cytoplasmic EPOR, possible differential structure and/or binding affinities of hematopoietic versus non-hematopoietic cell EPOR, possible aberrant regulation of EPOR activity, and a functional EPO/EPOR autocrine/paracrine loop. The modulation by rhEPO of tumor cell response to anticancer agents is coincident with modulation of multiple signaling pathways, BCL-2 family proteins, caspases and NFkB. The molecular interplay of pro-survival and pro-death signals, triggered by EPO and/or by anticancer agents, is multifactorial and tightly coordinated. Expression microarray analysis may prove critical for deciphering this potentially novel network and its broad spectrum of genes and proteins.

Serous peritoneal psammocarcinoma with an aggressive course: a case and review of the literature

BACKGROUND

Primary serous peritoneal psammocarcinoma (PSPP) is a rare variant of serous carcinoma characterized by massive psammoma body formation and low-grade cytological features. Patients with serous psammocarcinoma have a protracted clinical course and relatively favourable prognosis, although a more aggressive course of PSPP may occur.

CASE PRESENTATION

A 52-year-old woman suffering from abdominal pain with ascites and serum CA-125 level substantially elevated underwent an exploratory laparoscopy which revealed bulk disease. The pathology report detected PPSP at the FIGO stage IIIC. The patient received neoadjuvant chemotherapy (3 courses of paclitaxel/pegylated liposomal doxorubicin/carboplatin). Optimal interval debulking surgery was performed as the next step, followed by three courses of adjuvant chemotherapy (paclitaxel/carboplatin). Due to the fact that the patient had residual disease, at the second-look surgery she received consolidation therapy with intraperitoneal and intravenous chemotherapy carboplatin. Eight months after the completion of treatment the patient developed disease recurrence in the peritoneum. Palliative surgery (enterostomy) was performed. Furthermore, the patient received two lines of chemotherapy consisting of cyclophosphamide/cisplatin and then gemcitabine. After twenty five months she developed brain metastases, treated with palliative radiotherapy. The patient died twenty-eight months since her primary presentation of PSPP.

CONCLUSION

PSPP is an infrequent variant of epithelial cancer with favourable prognosis. The disease may however, take a more aggressive course. Thus, an aggressive therapy is required to postpone the progression.

Renal protection with magnesium subcarbonate and magnesium sulphate in patients with epithelial ovarian cancer after cisplatin and paclitaxel chemotherapy: a randomised phase II study

BACKGROUND

The aim of this study was to examine the effect of magnesium supplementation on nephrotoxicity accompanying standard cisplatin-based chemotherapy in patients with epithelial ovarian cancer (EOC).

PATIENTS AND METHODS

A double-blind, placebo-controlled, randomised study was conducted in which study arm magnesium sulphate (5 g) was administered before each course of standard chemotherapy with paclitaxel (135 mg/m(2)/24 h) plus cisplatin (75 mg/m(2)) every 3 weeks in patients with EOC. Magnesium subcarbonate (500 mg), three times per day orally, was administered during the treatment intervals. The control arm was administered a placebo instead of both magnesium salts. Magnesium serum levels (sMg) and GFR markers: serum levels of creatinine (sCr), Cockroft-Gault (ClCG) and Modification Diet of Renal Disease (MDRD) formulae were recorded before each cycle, and 3 weeks after the sixth course.

RESULTS

41 EOC patients were randomised and 40 were eligible. sMg varied significantly between the supplemented and placebo groups (p<0.0001). The control group showed a significantly greater decrease of GFR assessed by: sCr (p=0.0069), ClCG (p=0.0077) and MDRD (p=0.032) formulae compared with the magnesium supplemented group.

CONCLUSIONS

These results demonstrate the nephroprotective effect of magnesium supplementation during chemotherapy with cisplatin.

Cystatin C, an additional marker of ovarian cancer extent: A pilot study

16080

Background: Cystatin C is a cysteine protease inhibitor which has been recommended as the marker of glomerular filtration rate (GFR). We investigated significance of cystatin C in relation to ovarian cancer extent and its feasibility in assessment of renal function in patient with ovarian cancer (OC) who underwent chemotherapy. Methods: We prospectively included consecutive patients with OC who underwent chemotherapy : cisplatin 75 mg/m2 plus 24-hour infusion of paclitaxel 135 mg/m2 every three week after surgery. Before chemotherapy serum renal markers were noted as: creatinine (Cr), cystatin C (Cys C), albumin, creatinine clearance (ClCr) calculated by using 24-hour urine collection per 1.73 m2, creatinine clearance estimated with formulas Cocroft- Gault (ClCG) and Modification of Renal Disease (MDRD1), respectively. Results: Between February 2003 and January 2006 37 patients were enrolled onto this study. Median age 54 year (range from 28 to 68). Cystatin C and CrCl weakly correlated (R Spearman= -0.36; p=0,03). There were no correlation between cystatin C and other markers of GFR (serum creatinine, ClCG, MDRD1). We showed correlation between cystatin C and tumor extent revealed by spiral CT- scan (> 1 cm diameter) after surgery (R Spearman= 0.4; p=0.01), and CA 125 (R Spearman= 0.4, p=0.03). Cut-off values were established as medians for both factors, and patients with high and low values had no statistical differences in overall survival (log- rank test, p=0.9). Conclusions: We believe that cystatin C could imply OC extent in patients.This factor weakly was correlated with CrCl, and no correlated with other GFR parameters.

No significant financial relationships to disclose.

Control of aggressive fibromatosis by treatment with imatinib mesylate. A case report and review of the literature

OBJECTIVE

There has been only one report available that focuses on the treatment with imatinib mesylate of two individual persons with aggressive fibromatosis. The authors concluded that after long-term treatment, for 9 and 11 months, with imatinib mesylate, both patients demonstrated radiographic and clinical responses. The novel therapy should be considered as salvage in patients with aggressive fibromatosis expressed platelet-derived growth factor receptor-alfa, beta (PDGFR-alfa, PDGFR-beta), and/or c-kit, whose tumors are uncontrollable by the standard management. On the other hand, the number of kinases blocked by imatinib mesylate is notching up, for instance the tyrosine kinase, which is associated with macrophage-colony stimulating factor receptor (M-CSFR).

METHODS

The patient was suffering from aggressive fibromatosis after prior therapy including surgery (R2), radiotherapy, and systemic treatment with combination of tamoxifen and sulindac. The tumor specimen was immunostained for PDGFR-beta and c-kit (CD117), and PDGFR-alfa and cytokines platelet-derived growth factor-alfa and beta were not assessed. The tests for both assessed molecules revealed negative results. In spite of this, the patient underwent a unique treatment with imatinib mesylate at the dose of 400 mg orally once daily for 3 years and 2 months.

RESULTS

After three months of the therapy, radiographic (met criteria of SD but small decrease of the tumor was noted) and clinical responses were recorded for the first time. The same was seen after 6 and 13 months of therapy continuation with imatinib mesylate. Currently, the patient is treated with imatinib mesylate (400 mg orally once daily) without any toxicity effects. The last MRI revealed readily a smaller tumor (35 x 20 mm) after such a therapy lasted more than 3 years.

CONCLUSIONS

Treatment with imatinib mesylate has been a well-accepted therapy for chronic myelogenous leukemia (CML) and gastrointestinal stromal tumors (GIST). There have been established four kinases (p210(bcr/abl), c-kit, PDGFR-alfa, PDGFR-beta) suggested as the target for imatinib mesylate. Other potential targets will be discovered as it has lately been determined that M-CSFR kinase activity was blocked by imatinib mesylate. The salvage therapy for aggressive fibromatosis with imatinib mesylate seems to be an attractive opportunity for patients with the advanced disease, whose prior therapy failed.