Genomics Revolution in Cancer

Cancer used to be classified almost entirely by what a pathologist could see under a microscope. Dr. Shrinidhi Nathany, Consultant in Molecular Haematology and Oncology at Fortis Memorial Research Institute, Gurugram, opened a Jivo Healthcare masterclass for doctors across Africa by explaining how that has changed: the World Health Organization now classifies every tumour in the body by its underlying genomics, not just its appearance on a biopsy slide. Trained first in pathology before moving into molecular diagnostics, she walked through what genomic testing means in practice, for diagnosis, treatment selection and hereditary risk in cancer care. This guide draws on that session.

Why Genomics Now Decides How a Tumour Is Classified

Genetics is the study of individual genes and the disorders a single faulty gene can cause, visible somewhere in the patient's body. Genomics studies the alterations across the full set of genes, in the laboratory rather than at the bedside. Every person carries around 30,000 genes and is 99.9 percent identical to any other person; the 0.1 percent difference is what makes each person unique, and only about 1.5 percent of the genome codes for protein at all, which is the portion most cancer testing actually examines. Once a suspicious piece of tissue is removed by biopsy, its DNA is put through genome sequencing, also called next generation sequencing, to identify the alterations driving that specific cancer. Without a molecular report, a tumour can only be labelled 'not otherwise specified,' a designation that changes the treatment a patient receives. Every cancer must now undergo at least basic genomic sequencing to reach a firm diagnosis, a standard set by the National Comprehensive Cancer Network and endorsed by the European Society for Medical Oncology.

What the Rest of This Series Covers

The articles that follow this guide go deeper into germline versus somatic testing, how genomic sequencing changed precision treatment for stage 4 lung cancer, hereditary cancer risk and the case for family testing, pharmacogenomics and drug response, liquid biopsy for cancer screening, how next generation sequencing actually works in the lab, gene therapy and genome editing, and where genomics is used beyond cancer, including pre-marital screening and the barriers that still limit wider access.