Name: 什麼是癌症幹細胞？ (What are Cancer Stem Cells?)
Uploaded: 2021-01-14T05:08:33.000Z
Duration: 2 min 46 s
Description: 【看影片學英語】數萬部 YouTube 影片，搭配英漢字典即點即查，輕鬆掌握單字發音與用法，長久累積看電影不必再看字幕。

More than 100 years ago, a British doctor, John Beard, noted that cancer cells behaved

關係子句

much like human trophoblasts (embryonic cells), which are referred to today as stem cells.

In 1911, he published a book called, “The Enzyme Treatment of Cancer and Its Scientific

Basis,” in which he expounded on his theory that cancer was caused by these primitive

precursor cells, and that enzymes could be used to treat the disease.

Dr. Beard noticed that the placenta (which forms from part of the fertilized egg) had

many similarities to a tumor, in that it exhibits uncontrolled and invasive growth. Some tumors,

like placental cells, even secrete the hormone HCG. Placental cells multiply unchecked until

the fetal pancreas begins secreting enzymes, at which point the placenta stops growing.

This led Dr. Beard to the conclusion that enzymes might also inhibit the growth of tumor

Tests on mice implanted with tumors showed that injections of pancreatic enzymes caused

their tumors to shrink. Dr. Beard then tested enzymes on human patients, with positive results.

However, Dr. Beard’s theory never caught on with the scientific establishment, and

However, it appears that Dr. Beard was correct all along. New research shows that tumors

do in fact originate from stem cells, which form the basis for the recurrence of tumors,

and also for the development of chemotherapy resistance. Most forms of chemotherapy and

radiotherapy kill only the quickly-dividing progeny of cancer stem cells, temporarily

destroying the bulk of the tumor. However, if even one stem cell survives, it will soon