Mumbai: The Cancer Genome Atlas (TCGA) didn’t just expand cancer research it has rewrote the rulebook. It proved that tumours in different organs can share more in common than tumours within the same breast or lung. With drugs following data, classifications evolved, and survival curves has shifted. But the precision oncology still has a blind spot as more South Asians largely missing from TCGA, India faces a stark choice create its own genomic evidence or rely on imported insights that may not fully serve its patients.
At a recent ETHealthworld’s India Oncology Leadership summit panel experts Dr. Shantanu Chowdhury, Professor at CSIR–Institute of Genomics and Integrative Biology (IGIB); Dr. Sanjeeva Srivastava, Professor at IIT Bombay and Founder of Proteomica International; and Dr. Muzammil Shaikh, Principal Director – Medical Oncology at Nanavati Max Institute of Cancer Care. Moderated by Prathiba Raju, Senior Assistant Editor debated whether TCGA has taken India far enough, and what the next phase of Indian cancer genomics must look like.
TCGA has fundamentally reshaped how the world understands cancer. By decoding the molecular underpinnings of tumours across 33 cancer types, the panel discussed about on TCGA shifted oncology from an organ-centric discipline to one driven by genetic pathways. The bigger question on how far this landmark global initiative has taken India from discovery to real-world cancer care.
Opening the discussion, Dr. Chowdhury reflected on TCGA’s lasting scientific impact, said, “TCGA fundamentally changed how we understand cancer by showing that genetics—and the person’s genetics—matter more than organ labels.”
Drawing from over two decades of research experience, he emphasised that cancer biology can no longer be approached as a one-size-fits-all problem. “If you don’t understand the demon, you don’t know where the Achilles’ heel is—the point where you want to intervene.”
Before the TCGA era, he noted, chemotherapy regimens such as platinum-based therapies were administered broadly, often with severe toxicity. “Over time, TCGA showed us that genetics matters,” he said, adding that the project also revealed its own limitations. “TCGA is heavily underrepresented in the South Asian and Indian context. If cancer is intrinsically genetic, then what we learn from Western cohorts cannot be blindly applied here.”
One of TCGA’s most profound contributions has been the pan-cancer insight that shared molecular circuitry can malfunction across different organs. “What TCGA has taught us is that a similar genetic circuitry can go wrong across different tissues,” Dr. Chowdhury explained. “The circuit doesn’t care which organ it belongs to.” While organ-specific factors remain relevant, targeting shared pathways across tissues is increasingly becoming a therapeutic reality.
As research has grown more granular, so has the complexity. “More and more, cancer is about understanding the genetics of each tumour, and each tumour can be very different,” he said. “In fact, a tumour is a galaxy of tumours.” This, he argued, is why deep research underpins the concept of personalised oncology and why new drug discovery must continue beyond known pathways.
While TCGA delivered a genomic blueprint, translating genes into function requires another layer of biology. Addressing this gap, Dr.Srivastava highlighted the role of proteomics. “Genomics gives us the blueprint, but proteins tell us what is actually happening in the cell,” he said. “That’s where proteomics goes beyond TCGA.”
Referring to TCGA’s early glioblastoma studies, Dr. Srivastava explained how the Clinical Proteomic Tumor Analysis Consortium (CPTAC) evolved to add functional insight. “In gliomas, genomics alone could not correctly classify nearly 30 per cent of patients,” he noted.
“Proteomics revealed clear patterns, particularly in recurrent tumours, including kinase activity and post-translational modifications.” Genomics, he said, maps the landscape, while proteomics reveals which pathways are active, and therefore actionable.
Importantly, Dr. Srivastava sees India at a strategic inflection point. “India has an opportunity to avoid the mistake the US made—waiting a decade to add proteomics after genomics,” he said. “If we integrate genomics and proteomics from the beginning on the same samples, the value of the data multiplies.”
From the clinic, Dr. Shaikh described TCGA as nothing short of transformative. “From a clinician’s perspective, TCGA has been a game changer,” he said. “Our understanding of cancer biology has deepened enormously—we now know that lung cancer or breast cancer is not one disease.”
Molecular stratification has already translated into tangible patient benefits. “TCGA has enabled drug development that has changed patient outcomes,” Dr. Shaikh noted. “Stage-four ALK-positive lung cancer now has a five-year survival of nearly 75 percent.” However, he cautioned that data interpretation remains a challenge, especially for South Asian populations that are underrepresented in global datasets.
That gap is precisely what the Indian Breast Cancer Genome Atlas (IBGCA), launched in 2022, seeks to address. Explaining the initiative, Dr. Chowdhury said, “Some tests developed using TCGA data work spectacularly in the US and UK, but they are not as efficient in Indian patients. That was a key motivation behind launching this project.”
The consortium, involving ten hospitals across India, has already sequenced around 800 matched tumour–normal genomes with full clinical follow-up. “We are sequencing Indian patients, analysing Indian data, and doing the computation here in India—end to end,” he said. Early results suggest that recurrence and metastasis signatures reported in Western cohorts do not fully apply to Indian patients.
The ultimate goal, he stressed, is clinical impact at scale. “At the end of the day, you don’t give an NGS test to a patient,” Dr. Chowdhury said. “You give a small, affordable biomarker test—and that’s what this research is ultimately about.” By narrowing findings down to 20–25 gene panels and validating them using patient-derived organoids, the team aims to predict therapy response, including immunotherapy, in a cost-effective manner.
While these efforts mark an important step forward, the panel agreed that India’s cancer genomics journey is just beginning. TCGA, Dr. Chowdhury reminded the audience, did not deliver overnight breakthroughs. “TCGA did not become a drug in five years,” he said. “It took years of hard work, clinical trials, and validation. India must take the same hard steps there are no shortcuts.”
