of circulating tumor DNA obtained during a blood test in patients with diffuse
large B-cell lymphoma can reveal several aspects of the cancer without the need
for more invasive tests
- Patients with diffuse large B-cell lymphoma require
repeated lymph node biopsies to diagnose and follow up the patient for
recurrence following treatment
- Researchers offer a simple blood test that sequences
tiny bits of circulating tumor DNA and helps to diagnose the subtype as
well as to follow up the cancer
- The findings of the research could simplify the
management and increase efficacy of treatment in these patients
. This finding was published by researchers from
the Stanford University School of Medicine in the Science Translational Medicine
Diffuse large B-cell lymphoma
is a type of
blood cancer that affects the B lymphocytes. These cells are a part of the
immune system; they are a type of white blood cells that produce antibodies
which help to fight various infections.
‘Genetic tests on a blood sample could revolutionize the management of diffuse large B-cell lymphoma.’
Diffuse large B-cell
lymphoma is classified as a type of non-Hodgkin's lymphoma
produces small swellings all over the body (lymph node swellings) and also
affects several other parts of the body. It is more common in adults than in
Diagnosis of diffuse
large B-cell lymphoma requires a lymph node biopsy
. Treatment is with chemotherapy,
radiation and/ or stem cell
transplantation. The response to treatment varies with different subtypes of
the cancer. While some forms are curable, others are extremely difficult to
sequenced tiny bits of DNA from the blood of 92 patients with diffuse large
B-cell lymphoma. They used a technique called CAPP-Seq to identify several
mutations in the tumor gene and have found that they provide the following
- The cancer subtype can be determined through the
sequencing test. Since the
treatment and prognosis depends on the cancer subtype, this information is
extremely important. For example, patients with germinal center subtype
have a better prognosis as compared to those with activated B-cell-like
tumors. Since the subtypes respond differently to treatment, the treatment
can be individualized based on this information.
- Mutations that may be associated with drug resistance
can be detected. This helps in
deciding the choice of chemotherapy medications which will work
best for the patient. The researchers detected mutations which may
determine resistance to the anticancer medication ibrutinib.
- The level of circulating tumor DNA before treatment is
an indicator of the prognosis of the cancer.
Patients with lower initial circulating tumor DNA levels have better
chances of progression-free survival, while those with higher levels are
likely to have poorer outcomes.
- Repeated testing helps to detect any remaining cancer
following treatment and turned out to be better than radiological tests
for the same. It also detects
changes in the sequences over time which may indicate worsening of the
cancer into a more aggressive form. This information could be used to
change the treatment into a more intensive type to deal with the cancer.
In fact, repeated sequencing
enabled researchers to detect a relapse in the cancer at an average of six
months before the appearance of any symptoms.
The use of measurement
of circulating tumor DNA levels thus provides an easy method for the diagnosis
and determination of the outcome of diffuse large B-cell lymphoma. It permits
individualization of treatment and saves the already traumatized patient of the
trauma of repeated biopsies. Further studies in this field followed by
application of the findings to patients can definitely improve the management
of patients with the blood cancer.
- Scherer F et al. Distinct biological subtypes and patterns of genome evolution in lymphoma revealed by circulating tumor DNA. Science Translational Medicine 09 Nov 2016: Vol. 8, Issue 364, pp. 364ra155 DOI: 10.1126/scitranslmed.aai8545