Tempus xF

Question 1

What does ctDNA stand for?

Answer 1

Circulating Tumor DNA. Specific to DNA derived from a tumor.

Question 2

What does cfDNA stand for?

Answer 2

cell free DNA. DNA freely circulating in the bloodstream.

Question 3

Are we more interested in ctDNA?

Answer 3

Yes, because it’s coming from cells directly impacted by a tumor.

Question 4

What are CTC’s?

Answer 4

Circulating tumor cells. Cells that have broken off from the tumor.

Question 5

True or false- Liquid biopsy is a type of assay which tests ctDNA and or CTC’s?

Answer 5

Yes

Question 6

Explain a liquid biopsy test:

Answer 6

it’s a test done on a sample of blood to look for cancer cells from a tumor that are circulating in the blood or to look for DNA from tumor cells that are in the blood.

Question 7

Why is CTC and ctDNA important clinically?

Answer 7

• screening and early detecting of cancer
• real-time monitoring of therapy
• risk for metastatic relapse
• determine at level we see which mutations and which therapies are most effective
• determining which therapies are most appropriate and if that patient will have resistance to those therapies.

Question 8

Tumor shedding

Answer 8

Cells break off from the tumor and “shed” into the bloodstream.

Question 9

1.) Tumor invasion

Answer 9

may happen when a tumor invades a nearby blood or lymphatic vessel.

Question 10

2.) Necrosis

Answer 10

Due to a cell dying. Either due to treatment or naturally being released from the tumor.

Question 11

3.) Apoptosis

Answer 11

Same thing. Cell dying

Question 12

Tumor heterogeneity and clonal evolution:

Answer 12

different cells in a tumor have different profiles.

Question 13

Minimal residual disease

Answer 13

detection of cancer remaining in the body during or following treatment.

Question 14

clonal hematopoiesis

Answer 14

occurs when there is a somatic mutation in a stem cell and that mutation will appear in the blood cells which derived from that stem cell.

Question 15

When does this commonly happen?

Answer 15

happens naturally with age, but also commonly happens in genes associated with leukemia.

Question 16

Pro’s

Answer 16

Non-invasive
easily repeatable
minimal pain/risk in specimen collection
more comprehensive picture of disease
dynamic monitoring of disease control/resistance
potential to reveal tumor heterogeneity

Question 17

Con’s

Answer 17

detection complicated by low concentrations
false negatives are a concern
false positives due to CHIP
quality of sample may be impacted by minor protocol deviations
no RNA analysis, no incidental germline findings.

Question 18

What is Tempus xF?

Answer 18

a liquid biopsy test that examines both ctDNA and CTC. Both are analyzed together.

Question 19

Genes analyzed?

Answer 19

105 genes (SNV's/indels) 
7 gene rearrangements 
8 copy number gains/losses

Question 20

depth of coverage

Answer 20

5,000x (since the DNA is so small, we want to be 100% sure what we are seeing is accurate) *

Question 21

immunotherapy metrics

Answer 21

MSI-H only (MSI-High)*

Question 22

specimen requirements

Answer 22

• two streck tubes of peripheral blood (8.5mL)
• 4-10mL frozen plasma
• 50ng cfDNA extracted from double-spun plasma

Question 23

Turnaround time

Answer 23

10 days from sample received

blood should be received within 72 hours of a draw

Question 24

Not included

Answer 24

normal match incidental germline
RNA
TMB
IHC options

Question 25

How it works in the lab?

Answer 25

1) peripheral blood sample obtained (streck)
2) centrifuged blood sample to separate out plasma, white blood cells, and platelets/ red blood cells
3) isolate cfDNA from the plasma

Question 26

Streck tube- Centrifuge breakdown

Answer 26

Plasma- 55% of total blood
Buffy coat- <1% of total blood
Erythrocytes- 45% of total blood

Question 27

what’s a huge advantage with Tempus vs. competitors:

Answer 27

to be able to convert from a solid tumor test to liquid biopsy.

Question 28

Is there RNA in the xF test?

Answer 28

No. But we do show big gene rearrangements and fusions that are still detected by just seeing the DNA.

Question 29

Is there normal match with this test?

Answer 29

No.

Question 30

Included elements in this test:

Answer 30

• No normal match
• no MRD
• No incidental germline
• No RNA
• No TMB

Question 31

What’s the point of the xF test

Answer 31

To determine what treatment plans are best for the patient. Designed to come up with therapeutic options for a patient with cancer.