<p><span style="font-weight: 400;">The absence of symptoms is typical in the early stages of many cancers, which is why early detection is both crucial yet difficult to achieve. People usually don’t see a doctor until they feel thoroughly sick, but by this point any existing cancer has grown and spread, and survival rates are less promising. </span></p><p><div data-conversation-spotlight=""></div></p><p><span style="font-weight: 400;">What is unique about nasopharyngeal carcinoma is that its development is </span><a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4308653/"><span style="font-weight: 400;">linked</span></a><span style="font-weight: 400;"> to the Epstein-Barr virus, and each tumor cell of this particular throat cancer </span><a href="https://www.technologyreview.com/s/608601/cancer-blood-tests-score-early-success/"><span style="font-weight: 400;">carries</span></a><span style="font-weight: 400;"> the virus’ genome. </span><a href="http://www.hopkinsmedicine.org/news/media/releases/scientists_develop_blood_test_that_spots_tumor_derived_dna_in_people_with_early_stage_cancers"><span style="font-weight: 400;">Research</span></a><span style="font-weight: 400;"> shows that dying tumor cells shed small traces of their DNA into the bloodstream, even in the early stages of cancer, and this is what the Hong Kong team looked for in their study.</span></p><p><span style="font-weight: 400;">In 2013, Lo and his team of doctors began the study with the aid of the Chinese University of Hong Kong, using a simple, </span><a href="https://www.technologyreview.com/s/608601/cancer-blood-tests-score-early-success/"><span style="font-weight: 400;">inexpensive genetic blood test</span></a><span style="font-weight: 400;">. They searched for traces of the virus, which would then indicate the possibility of cancer. One in 10 men who tested positive for the virus were found to have nasopharyngeal carcinoma, and of the more than 19,000 men who tested negative, only one individual has since developed the disease.</span></p><p><b>The Search for a Pan-Cancer Blood Test</b></p><p><span style="font-weight: 400;">While the Hong Kong study adds evidence to </span><a href="http://www.hopkinsmedicine.org/news/media/releases/scientists_develop_blood_test_that_spots_tumor_derived_dna_in_people_with_early_stage_cancers"><span style="font-weight: 400;">other existing studies</span></a><span style="font-weight: 400;"> that prove liquid biopsies do work, not all cancer-seeking blood screenings are as simple, effective or affordable. The presence of the virus in tumor cells made nasopharyngeal carcinoma both </span><a href="https://www.technologyreview.com/s/608601/cancer-blood-tests-score-early-success/"><span style="font-weight: 400;">easy and cheap to find</span></a><span style="font-weight: 400;"> in comparison. In addition, the Hong Kong blood test is limited to detecting only one of </span><a href="https://home.cancerresearch/types-of-cancer/"><span style="font-weight: 400;">200 types of cancers</span></a><span style="font-weight: 400;">. </span></p><p><span style="font-weight: 400;">A research team at Johns Hopkins Sidney Kimmel Comprehensive Cancer Center has also developed a </span><a href="http://www.hopkinsmedicine.org/news/media/releases/scientists_develop_blood_test_that_spots_tumor_derived_dna_in_people_with_early_stage_cancers"><span style="font-weight: 400;">blood test to detect early-stage cancer</span></a><span style="font-weight: 400;">, and in their case they were able to look for and detect </span><a href="https://thesocialedgen.wpengine.com/technology-and-innovation/blood-test-detects-cancer/2/"><span style="font-weight: 400;">four common types of cancer</span></a><span style="font-weight: 400;">: colon, breast, lung and ovarian. But the </span><a href="http://www.hopkinsmedicine.org/news/media/releases/scientists_develop_blood_test_that_spots_tumor_derived_dna_in_people_with_early_stage_cancers"><span style="font-weight: 400;">cost and time-consuming complexity</span></a><span style="font-weight: 400;"> of their blood test at this time prohibits widespread and affordable commercial use. According to Lo, the Hong Kong blood test </span><a href="https://www.technologyreview.com/s/608601/cancer-blood-tests-score-early-success/"><span style="font-weight: 400;">isn’t ready</span></a><span style="font-weight: 400;"> for commercial use either.</span></p><p><span style="font-weight: 400;">But nonetheless, commercial interest for cancer screening tests are on the rise with many biomedical companies, including U.S. based company Grail, which has raised more than $1 billion in their </span><a href="https://www.technologyreview.com/s/608601/cancer-blood-tests-score-early-success/"><span style="font-weight: 400;">pursuit</span></a><span style="font-weight: 400;"> of an all-in-one “pan-cancer” blood test. Creating such a test is an incredible challenge, as it would be far more difficult than testing just for </span><span style="font-weight: 400;">one or even a handful of cancer types. With no virus to detect, Grail is instead using </span><a href="https://www.technologyreview.com/s/608601/cancer-blood-tests-score-early-success/"><span style="font-weight: 400;">high-speed sequencers</span></a><span style="font-weight: 400;"> to search with an all-encompassing wide net for nuanced mutations in a person’s DNA. </span></p><p><span style="font-weight: 400;">Unfortunately, Grail’s process is both </span><a href="https://www.technologyreview.com/s/608601/cancer-blood-tests-score-early-success/"><span style="font-weight: 400;">difficult and costly</span></a><span style="font-weight: 400;"> - to the tune of $1,000 per blood sample. The Hong Kong blood test for nasopharyngeal carcinoma </span><a href="https://www.technologyreview.com/s/608601/cancer-blood-tests-score-early-success/"><span style="font-weight: 400;">costs</span></a><span style="font-weight: 400;"> only $30, but that is largely due to the easier detection of the virus. The overall hope is that with time and further research, more tests will be developed that can detect a wider-range of cancers, and costs will go down. One day, a simple drop of blood could tell us all we need to know to defeat cancer.</span></p>
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