Testing the genetic profile of immune cells next to a melanoma could lead to more accurate diagnosis to spot whether a skin cancer is aggressive enough to spread, researchers from Italy have found.
Monica Rodolfo, PhD - an immunotherapy scientist at Italy's National Cancer Institute in Milan - led the study, which has been published in Cancer Research, a journal of the American Association for Cancer Research.
"Using the study of genetic profiles, we found that the sentinel node contains information useful to foresee whether or not a patient with melanoma will have an aggressive cancer," Rodolfo says, adding:
"Although this study has a relatively small number of patients, it provides proof-of-principle that the immune system is crucially involved in controlling tumor growth, and that sentinel nodes are endowed with precise information on cancer behavior."
The study found an association between a specific immune cell and more aggressive skin cancer.
Disease progression within 5 years was more likely for people with melanoma who had a specific subtype of cells, called CD30-positive T cells, in the lymph nodes closest to their tumors.
Lymph nodes are part of the immune system and drain products of the lymphatic defense, including white blood cells.
The authors introduce their study by explaining that a sentinel lymph node is the first to "receive lymphatic drainage from a tumor and represents a relevant immunologic barrier" against metastasis - spread of the skin cancer.
"We found that T cells bearing a marker called CD30 are more frequent in the sentinel nodes of patients with aggressive melanoma," Rodolfo explains, "and they are also found in the blood of patients with advanced disease."
"The clinical implications are clear and straight: finding a way to avoid further surgery and intensive therapies to those patients who are less likely to have a recurrence, and directing these treatments instead to patients who are at high risk for recurrence."
The study set out with an exploratory approach to pick out any genetic associations between lymph node biopsies and progression of disease - by looking for genetic differences between samples from patients at different stages of melanoma.
Samples were taken from 42 melanoma patients and 25 healthy controls, matched for age and sex.
In the results, the skin cancer that worsened within the 5 years of the study could have been set apart from the tumors that turned out representing a good outlook for patients.
The biopsy analysis found that this difference was held in genes related to the immune response.
Hope for treatment as well as diagnosis
The genetic findings may yield a target for the more individual treatment of melanomas, according to Rodolfo:
"Our results also encourage the genetic study of the sentinel node as a reliable tool to personalize patient treatment."
Rodolfo goes on to hypothesize that CD30-based treatments could restore melanoma patients' immune response against tumors.
"Considering that drugs directed against this molecule have recently been developed to treat lymphoma, this hypothesis might be easily tested in the near future," she adds.Other recent research against melanoma has also used genetic testing to diagnose the cancer's severity - a simple blood test may reveal spread of melanoma, according to a study presented in November 2013.