Oncology is learning to classify cancers by the molecular fault that drives them instead of the organ in which they arise. The results in some hard-to-treat cancers are striking, but the evidence base is thinner than the headlines suggest, and for India the real bottleneck is testing.
For more than a century, cancer has been named after its address. A tumour in the lung is lung cancer, one in the colon is colorectal cancer, and each address has had its own specialists, its own trials and its own drugs. That map is now being redrawn. A growing family of medicines is prescribed according to the genetic or molecular fault that drives a tumour, wherever in the body it happens to sit. The approach, known as tumour-agnostic or tissue-agnostic therapy, is the subject of New Scientist’s cover feature of 17 October, and it has moved in under a decade from a regulatory experiment to a recognised branch of precision oncology.
From address to mechanism
The turning point came in May 2017, when the US Food and Drug Administration approved the immunotherapy pembrolizumab for any advanced solid tumour showing a defect in DNA mismatch repair, a condition that leaves cancers riddled with mutations and unusually visible to the immune system. It was the first time the agency had cleared a cancer drug on the basis of a biomarker alone. Larotrectinib followed in 2018 for tumours carrying NTRK gene fusions; in the pooled trials behind that approval, about three-quarters of patients responded, across cancers as different as infant fibrosarcoma, salivary gland tumours and thyroid cancer.
A peer-reviewed review published in the journal Cancers in March 2026 counted nine such US approvals between 2017 and October 2025, built around six biomarkers: mismatch-repair deficiency, high tumour mutational burden, NTRK fusions, RET fusions, the BRAF V600E mutation and strong HER2 expression. The last of these brought antibody-drug conjugates, which deliver chemotherapy directly to marked cells, into the agnostic fold. European oncologists gave the field its own dedicated track at the ESMO Congress in Berlin in 2025, a sign that the idea is no longer treated as a curiosity.
Why the hardest cancers stand to gain
The promise is greatest where conventional options are weakest. Rare cancers seldom attract organ-specific trials because too few patients exist to fill them. Basket trials solve the arithmetic by enrolling patients according to a shared mutation, pooling a dozen tumour types into one study. For a child with an NTRK-driven sarcoma or an adult with a mismatch-repair-deficient cancer of the bile duct, a matched drug can produce deep and lasting responses where standard chemotherapy offers little.
The most quoted example is a small 2022 study at Memorial Sloan Kettering Cancer Center in New York, in which every one of the first twelve patients with mismatch-repair-deficient rectal cancer treated with the immunotherapy dostarlimab saw the tumour disappear, sparing them surgery and radiation. Results of that kind explain the excitement.
What the evidence does not yet show
The caution is equally important. Most agnostic approvals rest on single-arm basket trials with small and mixed groups of patients, judged by tumour shrinkage and not by randomised comparisons of survival. The Cancers review notes that entire categories, including thoracic and head-and-neck cancers, were thinly represented in the pivotal data, so doctors often have to extrapolate.
Biology also resists a clean rule. The tissue a cancer comes from still shapes how it behaves: BRAF-mutant melanoma responds well to BRAF inhibitors, whereas BRAF-mutant colorectal cancer largely shrugged off the same drugs when given alone, because the gut cell has an escape route the skin cell lacks. And the target mutations are uncommon. NTRK fusions are found in well under one per cent of solid tumours. Agnostic medicine can be transformative for the patients who qualify, but they remain a minority, and resistance frequently emerges over time.
Readers should also separate this clinical story from a parallel wave of laboratory news. In early November, groups at MIT and the University of California, San Francisco reported nanoparticle and engineered-cell approaches that eliminated tumours in mice. These are encouraging but preclinical findings, years from routine human use.
The Indian equation
India records an estimated 14 to 15 lakh new cancer cases a year, with a heavy burden of head-and-neck, cervical, breast and gastrointestinal cancers, many diagnosed late. For this population the rate-limiting step is not the drug but the test. A patient cannot receive a mutation-matched medicine unless the tumour has been profiled, and comprehensive next-generation sequencing remains expensive, concentrated in metropolitan centres and largely paid for out of pocket. Several agnostic drugs are either unavailable or priced far beyond the reach of most families.
There are grounds for measured optimism. Simple immunohistochemistry for mismatch-repair proteins and HER2 costs a fraction of sequencing and is within the capability of most pathology laboratories, and it identifies candidates for two of the six agnostic biomarkers. Indian generic and biosimilar manufacturers have a record of bringing down the price of oncology drugs once patents permit. Public cancer centres have begun running molecular tumour boards, where pathologists, geneticists and oncologists jointly interpret results.
The policy task is to make testing systematic: decide which biomarkers should be screened in which cancers, build reference laboratories outside the metros, and include validated tests and matched drugs in public insurance packages. India also has reason to generate its own evidence, since the pivotal trials enrolled few South Asian patients and under-represented the tumour types most common here.
Where the field goes next
Researchers are widening the list of targets and testing combinations to delay resistance. Liquid biopsy, which reads tumour DNA from a blood sample, could make profiling quicker and repeatable. Regulators, for their part, are asking for confirmatory data after accelerated approvals.
The honest summary is that tumour-agnostic therapy has not beaten cancer, and it will not replace the organ-based system that still guides most treatment. It has added a second axis to the map. For a defined set of patients, some with cancers once considered untreatable, that second axis already points to a better outcome.
