about liquid biopsy

1. LIQUID BIOPSY
Dr. Manan Shah
Dr. ML Harendra Kumar

2. CONTENTS
• Introduction
• Definition
• What comes under liquid biopsy
• Circulating tumor cells (CTCs)
• Circulating tumor DNAs (ctDNAs)
• A new addition in liquid biopsy
• Indications of liquid biopsy
• Comparisons of somatic mutation expression in
ctDNAs and primary tumour
• Tumour biopsy & liquid biopsy
• Summary
• References

3. Molecular diagnostic scheme representing
routine biological specimens and their
molecular alterations.

4. INTRODUCTION
• The diagnosis of cancer has undergone a
paradigm shift.
• No longer is cancer diagnosed only based
on morphological parameters.
• More and more the diagnostic algorithm is
supported by immunohistochemical and
molecular alterations at the DNA, mRNAs,
miRNAs and proteomic level.

5. INTRODUCTION
• Multiple platforms and technological
advances enable faster and cheaper analysis
of all these as well as the whole genome.
• Recent scientific advances in understanding
circulating tumor cells, cell-free DNA/RNA,
and exosomes in blood have laid a solid
foundation for the development of routine
molecular ‘liquid biopsies’.

6. INTRODUCTION
• This approach provides non-invasive access
to genetic information – somatic mutations,
epigenetic changes, and differential
expression – about the physiological
conditions of body and diseases.
• Liquid biopsy has the potential to provide
information about cancers without invasive
biopsy, using circulating biomarkers.

7. INTRODUCTION
• It opens a valuable avenue for cancer
screening and monitoring.
• With the rapid development of highly sensitive
and accurate technologies such as next-
generation sequencing, molecular ‘liquid
biopsies’ will quickly become a central piece
in the future.

8. INTRODUCTION
• These include proteins, RNAs and DNAs.
They can be used in,
• Detection
• Diagnosis
• Monitoring and
• Detection of recurrence of cancer.
• While protein-based tumour markers have
been used in routine pathology for many
years, the ability to detect mutations in
circulating DNA is relatively new.

9. DEFINITION
• Liquid biopsies are non-invasive
blood tests that detect circulating
tumour cells (CTCs) and fragments
of tumor DNA that are shed into
the blood from the primary tumour
and from metastatic sites.

12. CIRCULATING TUMOR CELLS

13. CIRCULATING TUMOR CELLS
• During late 19th century, T.R. Ashworth
first described the presence of epithelial
cells in the blood of a woman with
metastatic breast cancer that were similar
in appearance to her primary tumor cells.
• Indeed, many patients with a variety of
solid tumors, including breast cancer, have
detectable cancer cells circulating in the
bloodstream, so-called circulating tumor
cells (CTCs).

14. CIRCULATING TUMOR CELLS
• CTCs represent a rare cell population in
the blood, typically less than 10 cells/mL
compared with 1 million WBCs/mL
• However, the detection of CTCs within a
routine blood specimen provides an
opportunity to monitor cancer non-
invasively, in essence a liquid biopsy.

15. Circulating tumour cell (CTC)
enrichment technologies.

17. Analysis of CTCs
Yu et al. (2011) J Cell Biol

18. CIRCULATING TUMOR DNAs

22. EXOSOMES/MICROVESICLES

23. • Exosomes are actively released vesicles
(carrying RNA, DNA and protein) and can
function as inter-cellular messengers.

24. A NEW ADDITION IN LIQUID
BIOPSY…..

25. TUMOUR EDUCATED
PLATELATES

27. • Besides tumor cells and their products,
normal cells present in the tumor
microenvironment are also released
into the blood stream.
• These cells can harbor important
information about the tumor.

28. • Among which platelets have been
studied extensively and gave promising
results.
• The biology behind this new diagnostic
role of Tumor Educated Platelets
(TEPs) is the well-known interaction
between blood platelets and tumor
cells

29. • This interaction affects not only the
expression of relevant genes in tumor
cells, but also alters the RNA profile
of blood platelets.
• mRNA sequencing of TEPs can be
distinguished from the platelets of
healthy individuals.

31. INDICATION OF LIQUID BIOSPY
• To monitor residual disease in patients
with known mutations in the primary
tumor.
• To monitor treatment efficacy in patients
• To monitor disease progression and
tumor evolution (i.e. development of
tumor resistance).

32. • Help the physician explore other
options of treatment when the patient
is resistant to current therapies.
• Provide an alternative method for
biopsy when tissue is difficult to
obtain or not available, or when the
primary site of metastatic disease is
unknown.

33. • It also provide an alternative method for
biopsy when the quantity of tissue
obtained in a biopsy sample is limited and
traditional molecular genotyping is
requested.
• Provide prognostic information.

34. CANCER AND SOMATIC
MUTATIONS
• The majority of cancers arise after a series
of somatic gene mutations that
accumulate during an individual’s lifetime
• Identifying and understanding the somatic
alterations in an individual’s tumor can be
crucial in cancer diagnosis and in planning
personalized cancer treatment, monitoring
response to therapy, and identifying
cancer recurrence

35. CANCER AND SOMATIC
MUTATIONS
• Moreover, as a tumor progresses, some
times it continues to acquire additional
alterations that can affect the response to
therapeutic agents such as chemotherapy
or targeted therapies.
• Distant metastases can harbor unique
genomic characteristics not detectable in
the corresponding primary tumor of the
same patient

36. CANCER AND SOMATIC
MUTATIONS
• Moreover, metastases located at different
sites show a considerable intra-patient
heterogeneity.
• Thus, the mere analysis of the resected
primary tumor alone (current standard
practice in oncology) or, if possible, even re-
evaluation of tumor characteristics based on
the biopsy of the most accessible metastasis
may not reveal sufficient information for
treatment decisions

38. Novel diagnostic biomarkers used in the
clinic for various types of cancers and their
targeted drug therapy.

42. Is this the end of tissue biopsies?
“Tissue biopsy will remain the gold standard
for the next couple of years. As scientific
knowledge advances, researchers are
learning more about the potential of liquid
biopsies to detect mutations.

43. • At the moment, liquid biopsies are
recommended when a tissue biopsy is
difficult, such as in the case of lung
cancer, or when the original site of the
disease is unknown.

44. Liquid biopsies have a powerful role in
helping patients get to the right treatment.

45. CONCLUSION
• Molecular analysis of cancer is required to
optimise patient treatment
• New methods such as next generation
sequencing show immense promise for the
future
• Liquid biopsy is coming of age and will
change practice – it will enable oncologists
to use drugs intelligently to combat
changes in individual cancers as they
happen

52. references
• Tumor-Educated Platelets as Liquid
Biopsy in Cancer Patients (PDF Download
Available). Available from:
https://www.researchgate.net/publication/2
84112407_Tumor-
Educated_Platelets_as_Liquid_Biopsy_in_
Cancer_Patients [accessed Jul 18, 2017].

53. THANK YOU