[1] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Morphol, BR-14049900 Ribeirao Preto, SP, Brazil
[2] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Biochem, Ribeirao Preto, Brazil
[3] Univ Sao Paulo, Fac Med Ribeirao Preto, Dept Pathol, Ribeirao Preto, Brazil
[4] Imperial Canc Res Fund, London WC2A 3PX, England