Drawing on genetics, Indian companies are offering blood tests to ferret out cancers
While
the humble blood test has for long been the touchstone to catch diabetes,
malaria and
HIV,
companies are now drawing on knowledge from human genetics to make blood tests
smart
enough to fish out several kinds of cancers.
Earlier
this month, Strand Life Sciences, a Bengaluru-based company, began offering a
test
called
‘STRAND LB’ that claims to be able to detect traces of a tumour “from a simple
blood
draw”.
MedGenome,
another company based in Bengaluru — also announced the launch of
“ONCOTRACK”,
another ‘liquid biopsy’ test. “Management of cancer will undergo a
massive
transformation in India with NGS (next-generation sequencing)-based liquid
biopsies…
ONCOTRACK is one such offering,” says MedGenome chairman Sam Santhosh
in a
press statement.
Liquid
biopsies
NGS
refers to techniques to scan genes and look for mutations that may cause
cancer.
Traditionally,
ferreting out cancer requires scooping out tissue from a suspected organ and
testing
them for the disease. Depending on the location of the cancer, this frequently
involves
invasive
surgery.
Moreover,
even after surgery or chemotherapy, several more biopsies are continually
required
to check if the cancer has disappeared or worse, relapsed. Biopsies are also
required
to
check if the cancer is caused due to specific kinds of mutations that would
render certain
kinds
of treatment ineffective.
Liquid
biopsies, as these tests are called, involve being able to catch free-floating
pieces of a
tumour
or particular pieces of tumour DNA in the blood. These are then analysed to see
if the
DNA
contains mutations that are known to be linked to particular kinds of cancer.
The
trouble usually is that they are present in amounts too minuscule to be
detected. To have
a
shot at capture, any test has to be sharp enough to fish out about one molecule
in 1,000.
“STRAND
LB can detect tumour DNA traces in as many as 35% of patients with early-stage
cancer,
going up to 70-90% in patients with locally advanced or metastatic cancer.
These
figures
are on a par with the best in the world,” says Dr. Vijay Chandru, chairman and
managing
director, Strand Life Sciences. These numbers spanned a wide variety of cancer
types,
including lung, colorectal, breast, and bladder cancer.
According
to Dr. Chandru, liquid biopsy tests couldn’t yet be a replacement for
traditional
biopsies
but there were a variety of situations that made them useful — for instance,
lung
cancer
patients who couldn’t afford to part with enough tissue. These are important to
determine
if their tumours carry mutations in genes such as EGFR, making them eligible
for
specific
treatments. It can also be used to monitor the very same patients for the
emergence of
resistance
to these treatments.
The
cost barrier
Liquid
biopsy tests approximately cost ₹
15,000-₹ 20,000, making them roughly three-four
times
as costly as solid biopsies. However, proponents say the world over, liquid
biopsies are
considered
an emerging technology and it was quite likely that in the next five years
there
would
be blood tests powerful enough to find out if a seemingly healthy person has
been
struck
by cancer. “At least in the case of breast cancer, research shows that liquid
biopsies are
extremely
effective,” says Shantanu Chowdhury, a cancer researcher at the CSIR-Institute
of
Genomic
and Integrative Biology in Delhi.
India
is likely to have over 1.73 million new cases of cancer and over 8,80,000
deaths due to
the
disease by 2020. Around 70% of all cancer patients approach the doctor when the
disease
has
advanced and chances of a cure are very low.
Source: The
Hindu
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