The Nobel committee cited the pair for advancing "our knowledge from a stage when... growth factors were unknown, to a situation today when the role of growth factors in cell proliferation, organ differentiation, and tumour transformation is generally recognised."
Their work has helped understanding of such disorders as cancer, birth defects and Alzheimer's and Parkinson's diseases. Enjoying great affection and respect in Italy, Levi-Montalcini intervened to defend the teaching of evolution in schools when, in 2004, the then education minister, Letizia Moratti, wanted to remove it from the curriculum.
Born into a wealthy Jewish intellectual family in northern Turin in 1909, Levi-Montalcini was the daughter of an engineer and an artist.
In 2001, Italy's then president Carlo Azeglio Ciampi named Levi-Montalcini a Senator for life, an honour bestowed on former presidents and prominent figures in social, scientific, artistic or literary fields. In this role, she was the grand old lady of the Senate, taking pains to turn up for crucial votes in support of the Italian centre-left, even late in life when she was deaf and nearly blind.