Stem-Seq™ range
Frequently Asked Questions

Shall I choose WGS or targeted NGS to check for the genomic stability of my iPSC line?

The FDA’s latest draft guidelines on “Safety Testing of Human Allogeneic Cells Expanded for Use in Cell-Based Medical Products” recommend performing whole-genome sequencing (WGS) on cell banks of continuous cell lines and genome-edited cells, at a minimum read depth of 50x. While this represents an important regulatory baseline, a 50x WGS analysis has a key limitation: insufficient sensitivity for detecting low-level mosaicism. Since genomic abnormalities in hPSCs can arise at very low variant allele frequencies and rapidly expand to dominate a culture, early detection is critical. For this reason, Stem Genomics recommends complementing WGS with a targeted NGS (or dPCR test such as iCS-digital™ PSC) assay in your iPSC workflow is highly advisable. Its significantly deeper detection provides the sensitivity needed to identify emerging variants that WGS at 50x would likely miss, adding a meaningful layer of robustness to your genomic safety strategy. WGS in turn will provide a broader analysis to a targeted approach that will ensure a comprehensive view of the cell genome. Together, this will efficiently de-risk your final cell product.

What is the use of the backbone and PON in the Stem-Seq™ Plus assay?

As CNVs represent large regions of the genome, they are complex to analyze. Consequently, Stem Genomics introduced a backbone and a Pool of Normal (PON) in the Stem-Seq™ Plus assay to enable a more robust analysis of significant variants. The backbone of probes covers the entire genome. Combined with the PON, they enable data normalization between the target sample and the normal sample and effectively reduce background noise.

How is the report interpreted?

Specialists at Stem Genomics are committed to providing a comprehensive interpretation of single nucleotide variants (SNVs) by meticulously examining each variant in multiple databases such as Cosmic and ClinVar, as well as conducting an extensive literature review. In addition, for copy number variation (CNV) analysis, our team will prioritize your variant by comparing it against our proprietary database, the SMART database and the ACMG (American College of Medical Genetics and Genomics) classification standards.

What shall I look for when vendors offer WGS interpreted data?

Stem Genomics highlights the fact that there are several levels of interpretation in bioinformatics. First thing to check is if the analysis is fully automated or performed by an expert in your field, to ensure that pathogenic and clinically relevant insights are pulled out of the big data. Another aspect will be the accuracy of the analysis, that will be assisted by multiple variant callers and filters, leading to less false positives, a frequently encountered issue in WGS analysis. Additionally, it is important to know that not all vendors will support downstream interpretation and support you may need beyond the delivered results. Finally, the clarity of the report itself matters: results should be presented in a straightforward, accessible format that translates complex data into actionable insights, ensuring the findings can be readily integrated into the client’s QC process.

Is it possible to obtain the list of excluded variants as well as the rationale behind the exclusion?

Yes, it is. We offer a transparent and comprehensive analysis process, starting with the provision of the raw data containing all the variants identified in your samples.

How much does it cost?

The price will depend on the level of interpretation you require for the reports. Discounts are also available for large volume orders.

Is the assay relevant to all stem cell types?

The Stem-Seq™ range has been designed to provide pertinent information to all stem cell scientists working on human stem cells. It is particularly suited to pluripotent stem cell scientists who encounter the highest level of mutations in their cells.

Can I combine the iCS-digital™ assay range with the Stem-Seq™ range?

These Stem Genomics’ assays are complementary. Together, they will strengthen your stem cell workflow genomic stability. The iCS-digital™ range is ideal for regular in-process checks during amplification and maintenance and detects CNVs. As for the Duo iCS-Karyo, it will de facto detect CNVs, but will also show aneuploidies or chromosomal structural abnormalities such as translocations and inversions. The Stem-Seq™ range will complement these two tests at acquisition, banking characterization or end of workflow. It will complement the analysis with the identification of potential SNVs (punctual mutations) and small insertions/deletions (indels).

Is your assay range focused on genomic stability or can you support stem cell researchers with other useful assays that we can integrate into our QC?

In accordance with the ISSCR’s latest quality standard recommendations, Stem Genomics strongly recommends regularly checking the identity of your stem cells during their time in culture with our STR assay. Mycoplasma testing is also critical for robust science and we have a digital PCR solution called Myco-digital that can do that for you.

New WGS assay coming soon!

Unparalleled, comprehensive detection of SNVs, SVs/CNVs

Interpreted results by iPSC specialists

4-week turnaround

Important announcement for our US clients: we have moved!

As of July 17, our new address will be:

400 Park Offices Drive, Room 105

Research Triangle Park, Durham, North Carolina 27713

Please note that we will be closed from July 12 to 16

during the transition.

Download this file immediately

Please enter your details below

Access the webinar immediately

Please enter your details below

Upcoming webinar

Join us LIVE for a Q&A session on the latest iCS-digital™ PSC upgrade.

Find out what it means for you and ask all your questions

Juline VINCENT our R&D Project Manager and Digital PCR expert will answer you LIVE.

SAVE THE DATE: Thursday, November 7, 6pm CET/9am PDT/12 pm EDT.

Upcoming webinar

Join us LIVE for our webinar!

Best Practices: Making your hPSC Quality Control workflow more efficient

Join Juline VINCENT, our R&D Project Manager, as she presents efficient quality control strategies specifically designed to address the unique characteristics of pluripotent stem cells.

Thursday, October 23, 12:00 PM EST / 6:00 PM CET

Download this file immediately

Please enter your e-mail address.