RarePlex® ARv7/Synaptophysin CTC Panel Kit
Panel Kits – Enumeration | ARv7 | AR/ARv7 | SYP | ARv7/SYP | HER2/ER | PD-L1
Developer Kits – 405/488
Download Specification Sheets

RarePlex ARv7/SYP CTC Panel Kit

Prostate cancer (PC) is the second most common type of malignancy and one of the leading causes of cancer deaths in men worldwide.1,5 As androgen-mediated signaling is the predominant driver of PC proliferation,2 the androgen receptor (AR) is an important therapeutic target in prostate cancer where antiandrogens have been developed, primarily targeting the ligand-binding domain of the protein.3 Unfortunately, some patients may not benefit from the inhibition of AR activity or may develop secondary resistance. This resistance is observed in patients with circulating tumor cells (CTCs) containing androgen receptor splice variant 7 (Arv7), which lacks the ligand-binding domain, and correlates with poor treatment outcomes.

Overview of PSA Tumor Marker

Although antiandrogen resistance is mediated by AR signaling in some patients, the incidence of AR-independent PC is on the rise, in response to the introduction of more effective antiandrogens.6 One form of AR-independent PC, neuroendocrine PC (NEPC) is an aggressive form of PC that usually occurs in later stages of the disease, with resistance to earlier treatments6 and exhibits the expression of neuroendocrine markers, such as the most commonly expressed NEPC marker, Synaptophysin (SYP).4

PSA Testing with RarePlex AR-V7/Syp Panel

RareCyte’s ARv7 and SYP circulating tumor cell assay provides highly accurate, repeatable, and precise results for circulating tumor cell count, ARv7 and SYP biomarker expression, and is suitable for use in large, multi-center clinical trials of PC. This assay enables a blood-based investigation of two prominent mechanisms by which tumors become resistant to second line endocrine therapies. The assay includes processing blood to slides with the AccuCyte® Sample Preparation System followed by staining with the RarePlex 0919-LB ARv7/SYP CTC Panel Kit and imaging on a CyteFinder® Instrument. Machine learning enabled analysis and scoring maximizes reviewer concordance.

Benefits of PSA Tests with RarePlex AR-V7/Syp Panel

This ARv7/SYP assay, deployed on RareCyte’s circulating tumor cell analysis platform, provides:

  • Simple processing of blood to slides for sample banking
  • Convenient pause points in workflow enable sample control and transport
  • Flexible sample handling – processing and analysis may be performed at the same site or at a separate clinical research laboratory
  • Accurate and highly reproducible results
  • Worldwide network of contract research organizations (CROs) to support global clinical trials

Additional resources for the RarePlex ARv7/SYP Panel Kit

Order the panel kit →

Download the specification sheet →

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LEARN MORE about PSA Markers and other Biomarkers


22RV1 stained with the 0919-LB ARv7/Synaptophysin CTC Panel Kit
22RV1 stained with the 0919-LB ARv7/Synaptophysin CTC Panel Kit.
Scale bar represents 10μm.
Distribution of Synaptophysin MFI for mCTC across 5 slide replicates
Distribution of ARv7 (top) and SYP (bottom) MFI for spiked CTCs across 5 slide replicates per cell line for stainer run 1 (left), 2, (center), and 3 (right). The 22Rv1 cell line is positive for the expression both biomarkers, ARv7 and SYP and the BT-474 cell line is negative for the expression of both these biomarkers. Each box represents the 25th, 50th and 75th percentile of all cells within the 5 slides. Whiskers indicate the 10-90 percentile range. Dotted lines indicate thresholds (MFI=180 for ARv7 and MFI=120 for SYP) used to determine biomarker expression status on a per-cell basis.
RarePlex® Panel and Developer Assays for CTC enumeration and characterization

Presented by Arturo Ramirez, Ph.D., Director of Oncology R&D
This 7 minute overview of RarePlex Panel Kits and Developer technology highlights available circulating tumor cell assays from RareCyte and presents an introduction to our assay design and validation.

What is a PSA Marker?

PSA (Prostate-Specific Antigen) tumor marker is a protein that is produced by the prostate gland. PSA is widely used as a screening tool to detect prostate cancer and to monitor the effectiveness of treatment in patients who have been diagnosed with prostate cancer.

The PSA tumor marker is typically measured through a blood test, known as a PSA test. The test measures the amount of PSA in the blood, which can be an indication of prostate cancer or other prostate-related conditions. In healthy individuals, PSA levels are generally low, while in those with prostate cancer, the levels can be elevated.

However, PSA levels can also be elevated in non-cancerous conditions such as benign prostatic hyperplasia (BPH) and prostatitis, as well as in some cases of urinary tract infections. Therefore, a diagnosis of prostate cancer cannot be based solely on elevated PSA levels, and further tests such as a biopsy may be required. RareCyte’s ARv7 and SYP circulating tumor cell assay provides highly accurate, repeatable, and precise results for circulating tumor cell count, ARv7 and SYP biomarker expression, and is suitable for use in large, multi-center clinical trials of PC.

PSA testing has been the subject of much debate in recent years, with some experts arguing that over-reliance on PSA testing can lead to unnecessary biopsies and treatments, while others argue that it remains an important tool in the detection and monitoring of prostate cancer.

Despite these debates, PSA testing remains a widely used and valuable tool in the early detection and management of prostate cancer. It is recommended that men over the age of 50, or those at high risk of developing prostate cancer, undergo regular PSA testing as part of their healthcare routine.

  • Bray F, Ferlay J, Soerjomataram I, Siegel RL, Torre LA, Jemal A. Global cancer statistics 2018: GLOBOCAN estimates of incidence and mortality worldwide for 36 cancers in 185 countries [published correction appears in CA Cancer J Clin. 2020 Jul;70(4):313]. CA Cancer J Clin. 2018;68(6):394-424. doi:10.3322/caac.21492)
  • Cioni B, Nevedomskaya E, Melis MHM, et al. Loss of androgen receptor signaling in prostate cancer-associated fibroblasts (CAFs) promotes CCL2- and CXCL8-mediated cancer cell migration. Mol Oncol. 2018;12(8):1308-1323. doi:10.1002/1878-0261.12327
  • Helsen C, Van den Broeck T, Voet A, Prekovic S, Van Poppel H, Joniau S, Claessens F (August 2014). “Androgen receptor antagonists for prostate cancer therapy”. Endocrine-Related Cancer. 21 (4): T105–18. doi:10.1530/ERC-13-0545. PMID 24639562
  • Pal SK, He M, Chen L, et al. Synaptophysin expression on circulating tumor cells in patients with castration resistant prostate cancer undergoing treatment with abiraterone acetate or enzalutamide. Urol Oncol. 2018;36(4):162.e1-162.e6. doi:10.1016/j.urolonc.2017.12.006
  • Rawla P. Epidemiology of Prostate Cancer. World J Oncol. 2019;10(2):63-89. doi:10.14740/wjon1191
  • Yamada Y, Beltran H. Clinical and Biological Features of Neuroendocrine Prostate Cancer. Curr Oncol Rep. 2021;23(2):15. Published 2021 Jan 12. doi:10.1007/s11912-020-01003-9