Japanese researchers have developed a more accurate method that comes with high diagnostic power to screen against cervical cancer from mucus samples.

Cervical cancer has approximately 500,000 new cases diagnosed each year. But the number of people diagnosed with precursor lesions in the cervix — also known as cervical intraepithelial neoplasia (CIN) — is 20 times higher.

Researchers from Fujita Health University aimed to identify biomarkers that could assist in the early detection of cervical cancer.

Currently, the two most widely used screening procedures for these conditions are human papillomavirus (HPV) tests and cytology examinations. While cytology has rather low sensitivity for detecting CIN, HPV tests are highly sensitive. Yet HPV infections do not always lead to cervical lesions, resulting in poor specificity.

The new study, published in the journal Cancer Science, focussed on a series of compounds that showed abnormal expression in serum and cervical mucus samples in cervical cancer patients.

These findings could potentially revolutionise disease prevention strategies, said the team.

They initially looked to find how changes in local immunity are related to cervical cancer, and “aimed to study all the currently known microRNAs (miRNAs) associated with the development and progression of cervical tumours”, said Professor Takuma Fujii.

The team compared the miRNA and cytokine profiles from serum and mucus samples, collected from patients with cervical cancer or CIN, over approximately eight years.

Initial screening pointed out three candidate miRNAs and five candidate cytokines in serum, and five candidate miRNAs and seven candidate cytokines in mucus.

“While miRNAs and cytokines in serum showed limited diagnostic accuracy, a specific combination of miRNAs and cytokines in mucus samples proved much more promising. This suggests that focusing on changes in local expression levels, rather than serum levels, may offer a superior diagnostic strategy,” said the team.

“Our study, for the first time, demonstrates that analysing mucus samples can distinguish cervical tumours from normal tissues more accurately than serum samples,” Fujii said.