 "Why aren't cancer drugs better? The targets might be wrong")
A sex-specific group of ten plasma proteins were found to detect 18 different early-stage cancers, representing all major organs of the body, according to a study published in the British Medical Journal Oncology.
Researchers said that while cancers of kidney in men and colon in women were easier to detect using their test, bladder cancer in women and thyroid cancer in men were "more challenging but achieved with relatively high accuracy after optimisation". The proteins could also detect liver and ovarian cancers, among others.
The research team at Novelna Inc, the US company that designed the test, found that while each of these proteins, by itself, was only moderately accurate at picking up the disease at an early stage, it was highly accurate when combined with other proteins in the group.
They said that these proteins were particularly effective at picking up early-stage disease, even as they showed an ability to pick up stage I-III disease and all types of cancer.
The team said the findings could kick-start a new generation of screening tests for early detection of the disease, even as they acknowledged that the small sample size of their study (440 people) and the lack of information on co-existing conditions limit their wider applicability.
This approach would be useful, especially as cancer manifests in different sex-specific ways, including age at onset, cancer types, and genetic alterations, according to a linked editorial in the journal by Holli Loomans-Kropp from The Ohio State University, US.
She said, however, that "several problems need to be addressed before the multi-cancer early detection )(MCED) tests can be deployed at a population scale."
For the study, the researchers collected plasma samples from 440 people diagnosed with 18 different types of cancer before treatment and from 44 healthy blood donors.
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Then, in each sample, they measured more than 3,000 proteins strongly associated with cancer chemical pathways.
For the measurement, the researchers used a technology deploying antibodies and a statistical algorithm in a two-step process - antibodies for detecting the biological signature of any cancer, and the algorithm for identifying the tissue of origin and cancer subtypes.
Through elimination, the team found that a panel of 10 sex-specific proteins emerged that were differentially expressed among the plasma samples from cancer patients and healthy people.
They found these proteins identified 93 per cent of stage one cancers among men and 84 per cent among women.
They said the test registered a 99 per cent specificity and 90 per cent sensitivity in men, and 85 per cent sensitivity and 99 per cent specificity in women. While sensitivity refers to the chances of a test returning true positive results, specificity refers to the chances of the test returning true negative results.
The fact that these protein signatures differed significantly between men and women suggests that they are most likely sex-specific for all cancers, said the researchers.
Further, the "very low-level" presence of these plasma proteins highlighted their importance in detecting pre-cancerous and early-stage disease before a tumour has yet to have any substantial systemic impact, they said.
The team also found that a larger group of 150 proteins was found to be able to identify the tissue of origin of most cancers in more than 80 per cent of cases in both men and women.
"Our new generation protein-based plasma test has shown high sensitivity in detecting a variety of early-stage tumours in asymptomatic patients, making it a strong candidate for use as a population-wide screening tool that is not currently achievable with existing tests or techniques," the team wrote in the study.
(Only the headline and picture of this report may have been reworked by the Business Standard staff; the rest of the content is auto-generated from a syndicated feed.)
