Most cancers occur in the sheets of epithelial cells that line organs.

大部分肿瘤都发生在覆盖器官表面的上皮细胞层。

youdao

ONCOLOGISTS would like to be able to classify cancers not by whereabouts in the body they occur, but by their molecular origin.

识别癌症类别，可以不通过癌症出现在身体哪个部位，而是通过它们的分子源，这是肿瘤学家们希望做到的事。

youdao

Around 80% of cervical cancers and an even higher proportion of deaths occur in low-income countries.

约80%的宫颈癌病例以及更高的死亡率发生在低收入国家。

youdao

Eighty per cent of breast cancers occur in women over the age of fifty.

BBC: NEWS | Health | 'Breast risk' for the left-handed

The study only involved people 66 and older, but half of all kidney cancers occur in this age group.

WSJ: Study questions kidney cancer treatment in elderly

The risk of breast cancer increases with age and currently a third of all breast cancers occur in women aged 70 and over.

BBC: Week ahead