Researchers at Fudan University in Shanghai have identified a protein—hepatitis A virus cellular receptor 1, or HAVCR1—that could transform how doctors diagnose some of the rarest and most aggressive cancers: primary central nervous system lymphoma (PCNSL) and its ocular variant, primary vitreoretinal lymphoma (PVRL). The discovery, published in Clinical Chemistry, offers a path toward earlier detection, fewer invasive biopsies, and better treatment monitoring for conditions that have long been difficult to catch.
PCNSL is a rare but relentless cancer that affects the brain, spinal cord, or eyes and carries one of the poorest prognoses among white blood cell cancers. Cases have steadily increased over the past five decades, yet diagnosis remains a clinical puzzle. The current gold standard—measuring interleukin levels—achieves only 80–90% diagnostic accuracy. For patients with PVRL, the eye-specific form, the problem is even more acute: diagnosis can take up to two years and typically requires multiple biopsies, compared with just 35 days for PCNSL. Worse, PVRL frequently mimics uveitis, a common inflammatory eye condition, making misdiagnosis common. Because 60–90% of PVRL cases progress to brain-based PCNSL, delayed diagnosis carries serious consequences, increasing the risk of neurological complications and death.
The Fudan team set out to find a better way. Using advanced protein-screening technology, they analyzed eye fluid and cerebrospinal fluid samples from 378 participants: 199 with PVRL or PCNSL, and 179 with inflammatory conditions or no disease. HAVCR1 emerged as a standout candidate, appearing at much higher levels in patients with these lymphomas than in control groups.
The results were striking. In eye fluid from PVRL patients, HAVCR1 achieved diagnostic accuracy of 92–100%; in cerebrospinal fluid from PCNSL patients, accuracy reached 97–99%. Crucially, HAVCR1 reliably distinguished lymphoma from uveitis—a distinction that tripped up existing markers like IL-10 and IL-6, which can produce unclear results when inflammation is present. The researchers also discovered something elegant: HAVCR1 is produced primarily by tumor cells themselves, making it a cancer-specific signal rather than a general inflammation marker.
Perhaps equally important, HAVCR1 responded dynamically to treatment. Levels dropped after successful therapy and remained elevated in patients whose disease didn't fully respond—suggesting the biomarker could serve as a real-time monitor of treatment effectiveness and relapse risk.
The researchers acknowledged that additional validation across different laboratories and patient populations will be necessary before HAVCR1 enters routine clinical practice. Yet they expressed clear optimism: "HAVCR1 is a robust fluid-based biomarker for PCNSL and PVRL and has been validated in multiple cohorts and sample types." The dual capability—diagnosing cancer and tracking its response to treatment—makes it a rare find in the biomarker world.
For patients facing the diagnostic odyssey that PVRL currently demands, this work offers hope. A single, non-invasive fluid test could replace months of uncertainty and multiple painful procedures, catching disease earlier when treatment is most effective. For a condition affecting one of the body's most sensitive tissues, that shift toward precision and speed could prove life-changing.