We began our project with the intention of designing a convenient test kit. For inspiration, we first looked
to similar products already available on the market, such as pregnancy tests.
For our initial assessment, we conducted a survey to gauge the kind of detection kit that prospective buyers
and consumers are looking for. We based our survey off three commonly used test kits and asked people to
choose which one they preferred to use. Interestingly, out of the three kits provided, the results indicated
that people favored a dipstick test similar in design to a pregnancy test.
We sent out an international survey (in Japanese and English) via Instagram, Twitter and Facebook and
gathered over sixty responses. We gathered information on how much people knew about testing for breast
cancer and identified several trends with respondents’ basic knowledge regarding breast cancer and breast
cancer screening. Despite nearly half (45.9%) of our respondents having at least one close acquaintance or
family member with breast cancer, only 23% of respondents ever received breast cancer screening in their
lifetime. With regards to knowledge about breast cancer screening, only 27.9% correctly replied that breast
cancer testing should occur after around 40 years of age, while only 29.5% of respondents knew that breast
cancer testing should occur about once every 2 years.
When given multiple choices for what factors have prevented or would prevent respondents from getting
screened for breast cancer, “Cost” and being “Too busy” were selected as the most common responses (44.3%
and 42.6% respectively), followed by “Inconvenience” and “Lack of understanding of the risks of breast
cancer screening” (both 39.3%). Other factors repeatedly mentioned in the free response section of the
survey included the pain associated with breast cancer screening, as well as a reluctance to engage with the
Japanese medical system (in some cases, due to bad past experiences with government-sponsored screenings).
Finally, in order to determine if there would be a demand for an easy at-home breast cancer detection test,
we asked respondents whether they would be more willing to test frequently, or at all, if there were such a
test. The answers to this question were overwhelmingly positive, with 95.1% responding “yes”. Therefore, we
realized the importance of crafting a more convenient testing system, and made this the focus of our iGEM
project.
Our initial design involved a lateral flow assay, similar to the ones already pioneered for the detection of antigens by multiple research groups using aptamers. This design would be easy-to-use and minimally invasive.
In order to better understand the priorities of both health care providers and patients when it comes to
breast cancer testing methods, the team sent out two versions –one in English and one in Japanese– of a
survey in order to get insight into the Japanese community perspective and International community
perspective. Questions were asked on preferred testing methods, pricing, and the upsides/downsides of
various testing methods.
From the results, we found that both American and Japanese women favored a pregnancy test-like kit as a way
of detecting breast cancer biomarkers (52.2% of respondents scored a pregnancy test format as five out of
five on a one to five scale). The other options were a saliva test (similar to current coronavirus antigen
tests) and a finger-prick test (similar format to a blood glucose test), but many feared result inaccuracy
and invasiveness of the procedures respectively.
This resulted in only 21.7% of respondents scoring the saliva test as a five-out-of-five, and 30.4% of
respondents scoring the finger-prick test as a five-out-of-five on the scale. For pricing, many women
understood that it would be difficult to provide these kits for free, yet wanted detection kits at the
lowest prices possible. 43.5% of surveyed women believed that these detection kits should be available in
the 2,000 JPY to 4,000 JPY (~14.00 USD to ~28.00 USD*) range, while 47.8% answered that an ideal price range
would be 1,000 JPY to 2,000 JPY (~7.00 USD to ~14.00 USD*).
We met with Dr. Ikebukuro, who teaches at the Tokyo University of Agriculture and Technology, to discuss the
feasibility of a lateral flow assay. From our discussion, we learned that a lateral flow assay requires the
use of biotin and streptavidin to immobilize the aptamers, which is very difficult and unreliable.
Furthermore, the use of gold nanoparticles (the usual choice in lateral flow assays) presents a problem, in
that it is far too expensive and very hard to procure. Lastly, the lateral flow assay alone only allows for
a qualitative estimate of the biomarker level, which is not specific or sensitive enough to accurately
diagnose breast cancer. Therefore, in order to keep the kit relatively cost-effective while still
maintaining accuracy, we decided to switch from a dipstick-like lateral flow assay to a liquid biopsy, were
the sample is added (using a swab or a dipstick) to the aptamer solution before being placed under a well
plate reader to assess its fluorescence.
Initially, we were intent on adapting lateral flow assays in pursuit of this goal; however, technical
challenges and the relative sensitivity required to measure small fluctuations in biomarker concentration
indicated that this was not the best course of action. Therefore, we instead turned to highly sensitive
homogeneous immunoassays, such as the AlphaLISA test from Perkin-Elmer for inspiration.
Additionally, we interviewed Dr. Yuza and other hematologist-oncologists at the Tokyo Metropolitan Children’s Medical Center on the state of our current project. Specifically, we gave a presentation on the overview of the mechanism of our project, and received feedback on what we could do to improve the design of our detection kit. The findings are summarized below.
Over the summer, we researched oncologists’ interviews on the limitations of current breast cancer detection
methods. Due to the pressing COVID-19 pandemic, we were not able to contact as many healthcare workers to
interview. To make up for this, we sought out interviews already done by professional magazines such as the
“Doctors File,” a Japanese authoritative journal that compiles information on doctors nationwide, as well as
information on over 160,000 clinics and hospitals.
Reading up on oncologists’ explicitly stated methods of detection, we were able to gain professional insight
into what features appealed to those actually providing the test. We also obtained information on what
additional features or detection methods oncologists wanted to incorporate to reduce factors such as pain
and invasiveness. A few examples include 3D Mammograms or Painless MRIs. These detection methods accommodate
for patients’ varying breast features, such as the high concentration of mammary glands which is common in
younger patients and Japanese women at the age of 40 or under.
After our team gained a good understanding of the current testing options of breast ultrasound, breast
magnetic resonance imaging, diagnostics mammogram, and biopsy, our team came across Mrs. Shiho Azuma, the
CEO of Lily MedTech. She developed a breast ring-array ultrasound imaging system, "COCOLY," a unique,
non-invasive breast cancer detection method. The technology works where the patient lies on the machine
fully clothed and can get their results.
The implementation of these detection methods would greatly reduce the risk of late breast cancer detection.
However, all are costly. Current methods of detection are unable to eliminate factors of pain and
invasiveness while remaining inexpensive. Thereby stressing the need for an at-home breast cancer kit.
We have come to realize that a pregnancy test-like kit for the early detection of breast cancer will not be
very effective, as the fluctuations in biomarker levels between those affected with breast cancer and those
who are not is very small, and thus cannot simply be qualitatively detected through a simple test strip
(unlike hCG levels, which fluctuate greatly depending on whether a woman is pregnant or not).
Moreover, the iGEM judges at the 2021 Giant Jamboree provided us with feedback on the ethical aspect of our
project, as we proposed this detection kit to be administered at home by individuals. This was because it
would be best for patients to have explanations from doctors when receiving this detection kit and follow up
with them if the results of their test does show high levels of Mucin 1 and they require further testing. A
disease such as breast cancer should not be taken lightly, and the clinical setting will provide the support
that someone may need when they do receive their results.
Furthermore, many of the lateral flow assays we referenced also use fluorescence to improve the accuracy of
the test and allow the test to become at least semi-quantitative instead of purely qualitative. Therefore,
although we still believe in the importance of a simple and cost-effective method, we also believe that such
a method cannot be achieved as is without greatly sacrificing accuracy, specificity, and sensitivity.
Therefore, we decided to compromise and introduce some elements of the Covid 19 antigen test (the second
highest scoring test on our survey, with a similar average score to the pregnancy test) into our project to
increase its practicality and feasibility (considering that this was an important point raised during the
Giant Jamboree last year).
Therefore, we added a buffer component to our test, where the aptamer solution responsible for detecting our
biomarkers will be suspended in, which was inspired by the work of Yang et al and Wu et al. Not only does
this increase the stability of the aptamers (by controlling the pH), but it also ensures that fluctuations
in pH do not affect the results. Furthermore, we also modified the test to be read under a well plate reader
for increased accuracy.
After further consultation with stakeholders, we came to the conclusion that, surprisingly, a test kit that
could screen for multiple patients and biomarkers at once would actually be much more helpful in a clinical
setting. Furthermore, from our interviews with doctors, we learned that in Japan, adults are used to blood tests and may actually prefer them
over saliva (a result supported by our surveys), which indicated that a minimally invasive blood test
similar to existing liquid biopsies may be the best way forward. Henceforth, we completely abandoned the
idea of an individualized test kit, and instead focused on creating a technology that could be easily scaled
up to test many samples at once in a clinical setting, while still eschewing the laborious washing steps and
long incubation times demanded by traditional heterogeneous immunoassays.
Although the aim of our project has changed, we believe that this adjustment can actually improve the
feasibility of our project.
