Anti-Hu (ANNA-1) antibody is most classically associated with which cancer?

• A. Prostate cancer
• B. Breast cancer
• C. Small cell lung cancer
• D. Brain tumor

Answer: (C)

Anti-Hu antibodies are classic paraneoplastic antibodies that arise when a tumor expresses neuronal Hu antigens, most strongly in small cell lung cancer. Their presence reflects an autoimmune attack on the nervous system driven by the tumor’s expression of these antigens, often causing syndromes like sensory neuronopathy or brainstem/cerebellar involvement. Because of this strong association, small cell lung cancer is the cancer most classically linked to Anti-Hu (ANNA-1). Other cancers such as prostate, breast, or primary brain tumors are not the typical associations for this antibody. If Anti-Hu is detected, clinicians actively look for an underlying small cell lung cancer.