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這系列的第一集，我們講解了PD1/PDL1的運作原理。785Please respect copyright.ＰＥＮＡＮＡDZI7ZeWtLa
Link: https://www.penana.com/article/471125785Please respect copyright.ＰＥＮＡＮＡTcIcsLXTcM
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第二集我們講述CTLA4與T cell功用的關係。785Please respect copyright.ＰＥＮＡＮＡgvPewTGS9S
Link:https://www.penana.com/article/472480785Please respect copyright.ＰＥＮＡＮＡH4eIh1nZtN
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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。785Please respect copyright.ＰＥＮＡＮＡmVsaLGIiNU
https://www.penana.com/article/479229785Please respect copyright.ＰＥＮＡＮＡgouL7a41hY
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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。785Please respect copyright.ＰＥＮＡＮＡb5DUeiSVef
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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。785Please respect copyright.ＰＥＮＡＮＡkejOBILXYm
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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。785Please respect copyright.ＰＥＮＡＮＡxGgfPGotfA
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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。785Please respect copyright.ＰＥＮＡＮＡH9mLLocfEb
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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)。785Please respect copyright.ＰＥＮＡＮＡHFq3rxFJu9
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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。785Please respect copyright.ＰＥＮＡＮＡg127BYB6fM
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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，785Please respect copyright.ＰＥＮＡＮＡhThRxC8dSi
因此血液會有癌細胞的DNA。785Please respect copyright.ＰＥＮＡＮＡ03zoDpeBeC
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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。785Please respect copyright.ＰＥＮＡＮＡ3nGoZAFrUn
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在這裡，我們暫稱癌細胞在血液中的DNA為ctDNA，Circulating Tumor DNA。785Please respect copyright.ＰＥＮＡＮＡ3rU394cxUa
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（圖4）圖中為利用阻擋PD1的抗體Pembrolizumab作治療的兩名病人結果。785Please respect copyright.ＰＥＮＡＮＡbwgLvdKRex
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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。785Please respect copyright.ＰＥＮＡＮＡFiRtoqzL8Q
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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。785Please respect copyright.ＰＥＮＡＮＡ4U1M3gdAHy
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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。785Please respect copyright.ＰＥＮＡＮＡcqJ2895PPh
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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。785Please respect copyright.ＰＥＮＡＮＡUkw25ElAI0
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。785Please respect copyright.ＰＥＮＡＮＡxl8nvKmi2s
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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。785Please respect copyright.ＰＥＮＡＮＡznx5CqM5PO
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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。785Please respect copyright.ＰＥＮＡＮＡqaEoZq6pvm
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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。785Please respect copyright.ＰＥＮＡＮＡIwE3kjIewj
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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/toc785Please respect copyright.ＰＥＮＡＮＡaNWtU7bZtQ
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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。785Please respect copyright.ＰＥＮＡＮＡuWV5YcbfN3
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https://www.penana.com/user/27349/%E8%96%AF%E4%BB%94%E8%81%9E%E8%8C%B1%E8%8E%89/portfolio785Please respect copyright.ＰＥＮＡＮＡilZBV2Eiho
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有興趣接收科學資訊的話，歡迎follow IG: potatopigtongue。785Please respect copyright.ＰＥＮＡＮＡhVCE2XJpow
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https://www.instagram.com/potatopigtongue/785Please respect copyright.ＰＥＮＡＮＡO7r9SxSIyf
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Ref1:https://www.nature.com/articles/s43018-020-009785Please respect copyright.ＰＥＮＡＮＡKxxn9DJfdn
