Desafiar a Sabedoria Convencional

CAMBRIDGE – Quando terminei o meu doutoramento em 1974, tive a feliz oportunidade de fazer trabalhos de pós-doutoramento com Judah Folkman, da Escola de Medicina de Harvard. O Dr. Folkman desenvolvera uma teoria de que a progressão dos tumores poderia ser impedida se se cortasse a sua fonte de alimento. Sugeriu que os tumores emitem uma substância conhecida por factor de angiogénese tumoral, que faz com que os vasos sanguineos à volta do tumor cresçam na sua direcção, nutrindo-o e removendo desperdícios. Folkman estabeleceu a hipótese que este processo, a angiogénese, seria crucial para a sobrevivência do tumor.

Esta teoria chocava violentamente com a sabedoria convencional. Os cientistas que reviram os pressupostos de Folkman afirmaram que os novos vasos sanguíneos se deviam apenas à inflamação. Mas Folkman perseverou e acabou por provar que essas substâncias químicas existem de facto. Hoje, quatro décadas depois, essas substâncias foram usadas para tratar mais de 10 milhões de pessoas com doenças neovasculares como a degeneração macular e muitas outras formas de cancro.

Vivi uma experiência parecida enquanto trabalhava no seu laboratório, tentando isolar os primeiros inibidores do crescimento dos vasos sanguíneos (que eram substâncias de elevado peso molecular). Este processo requeria o desenvolvimento de um bioensaio que possibilitasse a observação da inibição do crescimento dos vasos sanguíneos na presença dos tumores.

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