HER2 (Human Epidermal Growth Factor Receptor 2) also known as Neu, ErbB-2, CD340 (cluster of differentiation 340) or p185 is a protein that in humans is encoded by the ERBB2 gene. HER2 is a member of the epidermal growth factor receptor (EGFR/ErbB) family. Amplification or over-expression of this gene has been shown to play an important role in the pathogenesis and progression of certain aggressive types of breast cancer and in recent years it has evolved to become an important biomarker and target of therapy for the disease.

HER2 is encoded by ERBB2, a known proto-oncogene located at the long arm of human chromosome 17(17q21-q22). HER2 is named because it has a similar structure to human epidermal growth factor receptor, or HER1. Neu is so named because it was derived from a rodent glioblastoma cell line, a type of neural tumor. ErbB-2 was named for its similarity to ERBB (avian erythroblastosis oncogene B), the oncogene later found to code for EGFR. Gene cloning showed that HER2, Neu, and ErbB-2 are all encoded by the same gene.

Neu! (trademarked NEU! in block capitals, German: New!, pronounced [ˈnɔʏ]) was a German band formed by Klaus Dinger and Michael Rother after their split from Kraftwerk in the early 1970s. Though the band had minimal commercial success during its existence, Neu! are retrospectively considered one of the founding fathers of Krautrock and a significant influence on artists including David Bowie, Brian Eno, Iggy Pop, PiL, Joy Division, Gary Numan, Ultravox, Simple Minds, Negativland, Stereolab, Boredoms, Radiohead, The Horrors, Electrelane, and much of the current electronic music scene.

Neu! was formed in 1971 in Düsseldorf as an offshoot from an early line-up of another seminal Krautrock band, Kraftwerk, whose early works were also produced by Conny Plank.

Drummer Klaus Dinger had joined Kraftwerk midway through sessions for their eponymous debut album. Guitarist Michael Rother was then recruited to the Kraftwerk line-up on completion of the album. (Rother had been playing in a local band called The Spirits of Sound, the line-up of which also included drummer Wolfgang Flür, who would himself go on to join Kraftwerk two years later.)