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這系列的第一集，我們講解了PD1/PDL1的運作原理。746Please respect copyright.ＰＥＮＡＮＡuFokZQ4WUg
Link: https://www.penana.com/article/471125746Please respect copyright.ＰＥＮＡＮＡhLRwvAJMtA
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第二集我們講述CTLA4與T cell功用的關係。746Please respect copyright.ＰＥＮＡＮＡNCxUkAtPSA
Link:https://www.penana.com/article/472480746Please respect copyright.ＰＥＮＡＮＡcnoMfbZjwf
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第三集我們講述增加T cell順利到達癌細胞位置的其中一種手段。746Please respect copyright.ＰＥＮＡＮＡi8fnngWvEt
https://www.penana.com/article/479229746Please respect copyright.ＰＥＮＡＮＡNjqH7sVqqe
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而這一集我們將講解一道關於檢測阻擋PD1的抗體Pembrolizumab成效的研究。746Please respect copyright.ＰＥＮＡＮＡjMNWtGxWL0
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關於阻檔PD1的原理及初心，可參閱第一集，其後可直接跳過第二第三集來到第四集本集。746Please respect copyright.ＰＥＮＡＮＡoVApH1MCuO
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（圖2）現今約只有20%的病人能夠從免疫治療中獲取長遠且持續的正面效果。746Please respect copyright.ＰＥＮＡＮＡwcyVNjZasE
746Please respect copyright.ＰＥＮＡＮＡif4Ejo0ZjI
746Please respect copyright.ＰＥＮＡＮＡFAhQeGbXw3
其有效的程度實屬可圈可點，如果有方法能夠盡快得知免疫治療沒有預期成效的話，那就可以即時轉用其他治療手段，把握時候嘗試用第二種方法入手打擊癌症。746Please respect copyright.ＰＥＮＡＮＡIqaWv8QsMR
746Please respect copyright.ＰＥＮＡＮＡBbJaRMcP3H
對此，有科學家嘗試量度血液中癌細胞的DNA含量，觀察能否藉此方法預判免疫治療的效果（Ref1)。746Please respect copyright.ＰＥＮＡＮＡiZVl1TJStR
746Please respect copyright.ＰＥＮＡＮＡCzSiLwj5bu
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(圖3）癌細胞DNA之所以會出現在血液中，主要由兩大途徑所成。746Please respect copyright.ＰＥＮＡＮＡyf0BLZ12uS
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1.癌細胞會利用血液循環系統或者淋巴系統轉移到第二個位置，746Please respect copyright.ＰＥＮＡＮＡ9yYr2hlsBx
因此血液會有癌細胞的DNA。746Please respect copyright.ＰＥＮＡＮＡHyPG8zr5wy
746Please respect copyright.ＰＥＮＡＮＡoSkJzIGBAR
2.癌細胞亦會往外釋出名Exosome的物質，裡頭亦含有癌細胞的DNA。746Please respect copyright.ＰＥＮＡＮＡ58l7XK0mAr
746Please respect copyright.ＰＥＮＡＮＡtVbR3CheN6
在這裡，我們暫稱癌細胞在血液中的DNA為ctDNA，Circulating Tumor DNA。746Please respect copyright.ＰＥＮＡＮＡAiNMY0hBJU
746Please respect copyright.ＰＥＮＡＮＡ0pMK1HI5DF
（圖4）圖中為利用阻擋PD1的抗體Pembrolizumab作治療的兩名病人結果。746Please respect copyright.ＰＥＮＡＮＡjL029LHfH7
746Please respect copyright.ＰＥＮＡＮＡ79ugA2jBdI
746Please respect copyright.ＰＥＮＡＮＡIOngMZDSN5
紅線為電腦斷層掃描觀察癌細胞大小的影像，而黑線為量度癌細胞在血液(ctDNA)的含量，可見黑線(量度ctDNA的含量)能夠更快預判免疫治療結果成效。746Please respect copyright.ＰＥＮＡＮＡjadwoZj7tI
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而且，有另外10名接受免疫治療的病人在初期(服用藥物後6-7星期)錄得ctDNA完全下降，亦同樣能夠比電腦斷層掃描觀察更早一步預判成效。746Please respect copyright.ＰＥＮＡＮＡrAKKJVOcnS
746Please respect copyright.ＰＥＮＡＮＡXWgAKhqaUO
而研究中有45名免疫治療的病人在初期沒有錄得任何的ctDNA跌幅，癌細胞的體積在其後亦沒有明顯縮細。746Please respect copyright.ＰＥＮＡＮＡ0Ll5QfkVUx
746Please respect copyright.ＰＥＮＡＮＡfiXK1Ke9Gp
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對比含放射性的電腦斷層掃描，量度血液的ctDNA只需抽取病人的血液便可，明顯簡單且快捷。746Please respect copyright.ＰＥＮＡＮＡLOcqyajzNS
只不過每名病人的ctDNA排組均不一樣，先前需要拿取部份癌細胞組織，才能夠有效設計檢測ctDNA的方針。746Please respect copyright.ＰＥＮＡＮＡY9jqMdaqec
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無論如何，若然日後能有研究進一步確立此方法的成效及可信性，定必大可增加對抗癌症的效益。746Please respect copyright.ＰＥＮＡＮＡKfWpBG9m5L
746Please respect copyright.ＰＥＮＡＮＡHzQ8SptCeF
另一方面，透過檢測血液的DNA來預先得知癌細胞的存在，亦是日後檢驗及預防癌症的主流大方向。746Please respect copyright.ＰＥＮＡＮＡQ5lcWhAWeR
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如果想我快啲出文的話，請入去Penana網站科普專欄–薯不揀單俾一個like以及Bookmark，這對我非常之重要。746Please respect copyright.ＰＥＮＡＮＡ0A6DZ5OH0E
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Link: https://www.penana.com/story/66244/%E7%A7%91%E6%99%AE%E5%B0%88%E6%AC%84-%E8%96%AF%E4%B8%8D%E6%8F%80%E5%96%AE/toc746Please respect copyright.ＰＥＮＡＮＡFYllXYAEEU
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同時亦可以在Penana網站裡按「買一嚿/半嚿薯仔」，以課金的方式推動我繼續搜羅資料寫文，多謝。746Please respect copyright.ＰＥＮＡＮＡ9u2k2VJOPD
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Link:746Please respect copyright.ＰＥＮＡＮＡRcB4Fnodr9
https://www.penana.com/user/27349/%E8%96%AF%E4%BB%94%E8%81%9E%E8%8C%B1%E8%8E%89/portfolio746Please respect copyright.ＰＥＮＡＮＡGNF59hJ32d
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有興趣接收科學資訊的話，歡迎follow IG: potatopigtongue。746Please respect copyright.ＰＥＮＡＮＡWOQvvURi0R
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https://www.instagram.com/potatopigtongue/746Please respect copyright.ＰＥＮＡＮＡobCvlPUlQp
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Ref1:https://www.nature.com/articles/s43018-020-009746Please respect copyright.ＰＥＮＡＮＡJBKgh04w5z
