A recently diagnosed case of small cell carcinoma of lung presented with slowly progressive proximal muscle weakness along with ptosis of eyelids and diplopia. O/E: – DTRs-absent Autonomic dysfunctions like frequent dryness of mouth were present. The doctor advised repetitive nerve stimulation test. There was increase in compound muscle action potential amplitude and this increase was >100% following exercise or with high frequency repetitive nerve stimulation. On serological testing, antibodies will be found against which channels: –