CGP 550 Plus and CGP 270 Plus Cancer Testing

How the panels differ and how to read a comprehensive genomic profile

Key takeaways

• CGP 270 Plus examines more than 270 cancer related genes using DNA and RNA from tumor tissue.
• CGP 550 Plus examines more than 550 genes and includes TMB & HRR in addition to the core alteration and MSI outputs.
• Both panels can assess single nucleotide variants indels copy number changes gene fusions and MSI according to the official materials and sample reports.
• The optional CGP 550 Plus with PD L1 combines NGS with a separate IHC assessment. PD L1 is not inferred from DNA or RNA sequencing.
• A broader panel is not automatically better. The right choice follows the tumor type treatment question earlier tests tissue available and current guidance.
• The report supports an oncology decision. It does not prescribe a medicine or guarantee that a listed therapy will work.

What comprehensive genomic profiling means

Both panels examine DNA and RNA from tumor tissue for several classes of genomic alteration. CGP 550 Plus expands the gene breadth and includes TMB while panel selection depends on the tumor type, prior testing, tissue, and the clinical question.

Official sample reports illustrate the structure and verified analytic scope of the two tests. Individual findings vary and a sample report should never be used to interpret another person's tumor.^[4][5]

Comprehensive genomic profiling examines many cancer related genes in one assay. Instead of looking for only one alteration at a time, it can search across several alteration classes and biomarkers that may help explain how a tumor is growing or whether a treatment or clinical trial warrants review.

What actionable means

An actionable finding is one that has evidence connecting it to a diagnosis prognosis treatment resistance treatment sensitivity or clinical trial. Actionability is graded, context dependent, and time sensitive. A finding in one cancer type may not carry the same meaning in another.

Term	Plain language meaning
Somatic alteration	A change detected in the tumor that may have arisen during the cancer
Biomarker	A measurable tumor feature that may inform care
Evidence tier	A structured indication of how strong and relevant the clinical evidence is
Clinical trial match	A study worth reviewing not an assurance of eligibility or access

What the panels can detect

Both panels look for multiple alteration types. The exact genes and regions differ, and not every alteration is detectable in every specimen. The test catalog and report methodology should be checked for the current scope.^[1][2][4][5]

Alteration	What it means	270 Plus	550 Plus
SNV	A change in one DNA letter	Included	Included
Indel	A short insertion or deletion	Included	Included
Copy number	Gain or loss of gene copies	Included	Included
Gene fusion	Parts of two genes join	Included	Included
MSI	Instability in repeated DNA	Included	Included
TMB	Mutation burden across the tumor	Not listed	Included

How the panels differ

Feature	CGP 270 Plus	CGP 550 Plus
Gene breadth	More than 270 cancer related genes	More than 550 cancer related genes
Nucleic acids	DNA and RNA	DNA and RNA
Core alteration classes	SNVs indels copy number changes fusions MSI	SNVs indels copy number changes fusions MSI
TMB	Not listed as a formal output	Included
Expanded analyses	Focused panel scope	Methodology describes additional HRD related LOH and aneuploidy analyses
PD L1 option	Not listed as a combined product	Separate combined product uses NGS plus PD L1 IHC
Official test code	SMO10765	OMO1034
Listed report time	11 days after an adequate sample	11 days after an adequate sample

Panel gene groups in a methodology section can overlap. Subtotals for hotspot genes copy number genes coding regions or fusions should not be added together to invent a unique gene count.^[5]

Choosing a panel

The choice should begin with the decision the oncology team is trying to make. Broader testing can be useful when the tumor has many potentially relevant genes, when several standard biomarkers need to be assessed together, or when earlier limited tests did not answer the clinical question. A more focused panel may be enough when the required targets are known and tissue needs to be conserved.

Factors to discuss

• Cancer type stage and current treatment setting
• Biomarkers recommended in current clinical guidelines
• Results from earlier single gene small panel or IHC tests
• Whether MSI TMB HRD related information or PD L1 is relevant
• Amount and quality of tissue available
• Whether a result could change treatment trial screening or another diagnostic step

The optional PD L1 combination

OncqSol CGP 550 Plus with PD L1 is listed as a distinct product using NGS plus IHC. The PD L1 result comes from an antibody based tissue stain and has its own scoring and tumor specific interpretation. It should not be described as a DNA or RNA sequencing output.^[3]

What sample is needed

Verified Oncquest offering facts

1

DNA and RNA analysis

The OncqSol CGP panels analyze both DNA and RNA.

Why it matters for you

DNA analysis is useful for sequence changes and copy number changes. RNA analysis can improve the assessment of expressed gene fusions and other transcript level events.

2

Listed turnaround

The current Oncquest catalog lists an 11 day report turnaround for both panels.

Why it matters for you

This is a service estimate after an adequate specimen is accepted and may change with logistics quality review repeat testing or holidays.

The official catalog lists formalin fixed paraffin embedded tumor tissue for both panels. The pathology team should select a representative tumor block or permitted unstained slides and provide the requested histopathology report and clinical history. Current submission rules should be confirmed before dispatch.^[1][2]

For CGP 550 Plus, the catalog asks for tissue with 40 percent tumor content verified by the in house pathologist. Requirements can depend on specimen size necrosis and DNA or RNA quality, so the laboratory must make the final adequacy decision.

• Label the specimen and requisition consistently
• Include tumor site diagnosis stage and relevant treatment history
• Send the pathology report and identify the selected block
• Ask before exhausting a small specimen that may be needed for other tests
• Confirm fixation slide age transport and minimum material requirements

From sample to report

1. Accession
   The laboratory matches the specimen request and clinical information.
2. Pathology review
   A pathologist verifies tumor and selects the area for extraction.
3. DNA and RNA extraction
   Nucleic acids are isolated and checked for quality and quantity.
4. Sequencing
   Targeted regions are read at high depth and RNA is assessed for relevant events.
5. Bioinformatics
   Alterations and biomarkers are called filtered and annotated.
6. Clinical interpretation
   Findings are assigned evidence tiers and reviewed in the tumor context.
7. Report release
   The report and any decision support appendix are issued to the care team.

Why quality review matters

Low tumor fraction degraded FFPE material limited RNA and uneven coverage can reduce sensitivity. A report may contain a quality note or state that part of the requested analysis could not be completed. That limitation is part of the result and should be reviewed before interpreting a negative finding.

How to read the report

1. Confirm identity
   Check patient specimen tumor site and report date.
2. Read adequacy
   Review tumor content coverage and assay limitation statements.
3. Find the summary
   Identify reported alterations MSI and where applicable TMB or HRD related biomarkers.
4. Check the details
   Review gene transcript coding and protein change read depth and variant allele fraction.
5. Review the evidence tier
   Tier I and Tier II indicate stronger clinical relevance than Tier III in the AMP ASCO CAP framework.
6. Separate evidence from recommendation
   A therapy association or trial listing requires tumor specific clinician review.

The sample reports use an AMP ASCO CAP tier framework. The professional consensus describes a four tier system and emphasizes that classifications should be reevaluated as evidence develops.^[6]

If a result label conflicts with its score or nearby explanatory wording, stop and request clarification or a corrected report from the issuing laboratory. Do not infer the intended meaning or use the ambiguous line for a treatment decision.

Tumor testing and inherited risk

CGP performed on tumor tissue primarily identifies somatic alterations. Some results can raise the possibility of an inherited variant, but a tumor only result usually cannot establish whether the alteration was inherited or arose only in the cancer.^[7][8]

When germline confirmation may be considered

• The gene and alteration are associated with an inherited cancer syndrome
• The variant allele fraction and tumor context make an inherited origin plausible
• The patient has an early age at diagnosis multiple cancers or a suggestive family history
• Current professional guidance recommends confirmation for that finding

Confirmation uses a separate blood saliva or other non tumor sample with informed consent and appropriate genetic counselling. Relatives should not be tested on the basis of a tumor result alone.

Limitations and follow up

• A negative report does not rule out every cancer driver or every therapeutic option.
• Alterations outside the genes regions or variant types validated by the assay may not be detected.
• Low tumor content FFPE damage tumor heterogeneity and technical coverage can reduce sensitivity.
• A detected alteration may not be active in every tumor cell and may not predict treatment benefit.
• A variant of uncertain significance should not generally direct treatment by itself.
• Evidence tiers therapy associations trial status approvals and drug availability can change.
• The assay does not replace pathology staging imaging organ function tests or every disease specific biomarker.

Plan the next step

For each important finding, ask whether it is diagnostic prognostic predictive or uncertain; whether confirmation is needed; whether the evidence applies to this tumor type; and whether the proposed treatment or trial is available and appropriate. A molecular tumor board may help when findings are complex.

Frequently asked questions

FAQs

Does CGP find every cancer mutation

No. It tests validated genes regions and alteration types. Tissue quality tumor fraction coverage and tumor heterogeneity also affect detection.

Is CGP 550 Plus always better than CGP 270 Plus

Yes. The broader panel can answer additional questions, but the best choice depends on the tumor type clinical need previous results tissue and current guidance.

Does CGP 270 Plus report TMB

TMB is not listed as a formal CGP 270 Plus output in the current catalog or attached sample report. It is explicitly listed for CGP 550 Plus. Confirm the current assay scope when ordering.^[1][2][4][5]

Is PD L1 included in every CGP 550 Plus order

No. Oncquest lists a separate CGP 550 Plus with PD L1 product. PD L1 is assessed by IHC and should be interpreted using the relevant tumor specific scoring method.^[3]

Can a report prescribe a treatment

No. It can identify evidence linked to therapies or trials, but the oncology team must assess tumor type approval status prior treatment health interactions access and patient preferences.

Does a tumor result show inherited risk

Not by itself. A finding that may be inherited requires genetic counselling and confirmation in a non tumor sample before family implications are considered.^[8]

How long will testing take

The current catalog lists 11 days after an adequate sample is accepted for both panels. Confirm the estimate because sample review logistics or repeat analysis can affect timing.^[1][2]

What if two parts of a report seem inconsistent

Ask the issuing laboratory to clarify or amend the report before the disputed result is used. The care team should not guess which statement is correct.

Sources

1. OncqSol CGP 270 Plus Test Details Official test scope specimen and turnaround information
2. OncqSol CGP 550 Plus Test Details Official test scope specimen and turnaround information
3. OncqSol CGP 550 Plus with PD L1 Test Details Official description of the combined NGS and IHC product
4. Official CGP 270 Plus Sample Report Report structure methodology analytic scope and limitations
5. Official CGP 550 Plus Sample Report Report structure methodology analytic scope and limitations
6. AMP ASCO CAP Somatic Variant Reporting Consensus Professional framework for evidence tiers and ongoing reevaluation
7. National Cancer Institute Biomarker Testing Patient information about tumor biomarker testing and its limits
8. National Cancer Institute Genetic Testing Fact Sheet Patient information distinguishing inherited genetic testing