Predicting whether early-stage cancer growths will develop into full-blown tumors is no easy task, as most growths look the same under a microscope. While some of them turn out to be benign, others morph into deadly tumors that advance and spread aggressively.
However, a recent study done on potentially malignant tumors in the lung has shown that it is possible to predict the likelihood of a growth progressing into cancer by studying its genetic makeup. This new theory is a tantalizing prospect into the future of cancer diagnosis.
The Answer Could Be In The Cell’s Genetic Profile
In a recent article published in Nature Medicine, a team of researchers led by Vitor H. Teixeira found that analyzing factors such as gene expression, DNA sequence deletions, and alterations of chromosomal structure, provided enough data that could be used to predict whether a given mass would regress into a benign tumor or progress into cancer.
The researchers pointed their sights on 129 samples of a non-invasive cancer called carcinoma in situ (a Latin term meaning “on-site” or “local”) obtained from 85 people. The samples then underwent a variety of tests to determine their genetic makeup, such as DNA sequencing, RNA expression analysis, and methylation profile testing.
Altering The Cells At Molecular Levels Before Cancer
Twenty-nine of the samples they subjected to DNA-sequence analysis were retrieved from patients who later had advanced lung cancer, while 10 other samples DNA-sequenced samples conversely came from patients who would later turn out to have non-cancerous growths. Their results were particularly striking.
Most of the samples that would later progress to cancer were found to have a mutation in their TP53 gene, a gene that helps impede the growth and development of cancer. The regressive samples meanwhile, had fully-functioning TP53 genes. The cancer-progressive samples also showed certain patterns of abnormalities in their chromosomes that are typically present in certain types of tumors. The researchers also found that analyzing the DNA methylation of the samples yielded important clues about how the growths were developing.
DNA methylation is the process through which methyl groups are added to DNA, thereby changing gene expression. It is responsible for certain processes that occur within the body, such as gene regulation, development and aging, as well as cancer formation.
Using statistical data analysis methods, the researchers discovered that the patterns of DNA methylation demonstrated by the regressive cells were like those of normal cells, showing that it is indeed possible to use genetic testing such as DNA methylation data.
Teixeira and his team then created a set of gene expression profiles for specific methylated DNA sequences and gene copy-number abnormalities that could be used to predict the likelihood of an in situ carcinoma developing into a cancerous growth.
During subsequent testing on samples retained for future use and samples procured from The Cancer Genome Atlas project, the team found that the profiles were remarkably precise in determining the probability of tumor development in the target samples. Their work offers a glimpse of a future in which precancerous growths are used to accurately estimate the likelihood of the person developing invasive cancer.