B細胞淋巴瘤二型(Bcl2)蛋白家族是一個與細胞凋亡相關的蛋白家族。Bcl2家族的蛋白在結構上及序列上具有同源性，且至少都包含了一個結構同源區(BH)，目前已知有BH1、BH2、BH3與BH4四種不同的BH序列。因結構上的差異性, 造就了促凋亡(pro-apoptosis)及抗凋亡(anti-apoptosis)兩種不同作用機制的蛋白。Bcl2L12是Bcl2蛋白家族中的新成員，已知Bcl2L12有兩個具有生物功能的轉錄變異體(transcription variants)，其中一個含有七個編碼的外顯子(exon)，可生成一個含有344個胺基酸的Bcl2L12蛋白，而另一個則由176個胺基酸(不含exon 3)組成的BcL2L12A蛋白。研究顯示在惡性腦瘤(GBMs)中，Bcl2L12的抗細胞凋亡特性是透過抑制caspase-3及caspase-7而阻斷後線粒體的凋亡信號(post-mitochondrial apoptotic signaling)。而在乳癌細胞(MDA-MB231)中也發現Bcl2L12mRNA的表現量可能與化療藥物所誘發細胞凋亡的抗性有關。雖然，過去的研究顯示Bcl2L12與Bcl2L12A均表現於細胞核內，但其所扮演的角色仍未被完全釐清。因此，本研究收集了106個不同病理分期的乳癌石蠟包埋檢體，分別對Bcl2L12以及Bcl2L12A mRNA的表現對乳癌的次分類進行探討。利用定量PCR (quantitative PCR) 偵測Bcl2L12與Bcl2L12A二者的表現量；並以統計方法分析Bcl2L12Bcl2L12A mRNA與乳癌臨床病理特徵之間的關係。結果發現Bcl2L12與Bcl2L12A mRNA的表現量分別在一般分期、病理分期以及TNM分期中並無顯著性的差異(p=0.073, p=0.651; p=0.756, p=0.986; p=0.342, p=0.634)。在線性迴歸分析中，Bcl2L12 mRNA的表現量對Bcl2L12A mRNA、第三期乳癌以及三陰性乳癌有關 (p<0.001, p=0.032, p=0.049)。而 Bcl2L12A mRNA的表現量則與Bcl2L12 mRNA (p=0.003)以及轉移的淋巴結數目(p=0.018)呈現正相關。然而，在非三陰性乳癌檢體中，Bcl2L12 mRNA的表現量只與Bcl2L12A mRNA有相關(p=0.001), 且在淋巴結數目≥12的檢體有較高的表現量(p=0.021)，即Bcl2L12 mRNA的表現量與較高的病理分期以及三陰性乳癌有關；再者，在非三陰性乳癌檢體中，Bcl2L12 與Bcl2L12A可能互有關聯性, 進而影響乳癌淋巴結轉移的嚴重程度。

The Bcl2 family is an apoptosis-related protein family. The Bcl2 family proteins share a high sequence homology; member of Bcl2 family proteins contains at least one of the homology domains (BH), which includes BH1, BH2, BH3 and BH4. The family protein comprises pro-apoptotic and anti-apoptotic members based on their structural and functional features. Bcl2L12 (Bcl2-like protein 12) is a novel member to the Bcl-2 family and two splicing variants of the Bcl2L12 gene are recently known. One consists of 7 coding exons and produces a protein of 334 amino acids (Bcl2L12); the other lacks exon3 and gives rise to a protein of 176 amino acids (Bcl2L12A). Bcl2L12 plays a role in post-mitochondrial apoptotic singling through multiple mechanisms involving p53, B-crystalline, caspase-3 and -7 in glioblastoma; besides, the Bcl2L12 mRNA expression may associate with the chemotherapeutic reagents-induced apoptosis in breast adenocarcinoma cells (MDA-MB-231). Bcl2L12 is reported to be a good prognostic marker in breast cancer and correlated with ER and Bcl2 expression status. However, the mechanisms by which Bcl2L12 regulates apoptosis in breast cancer still remain unknown. Therefore, a total of 106 paraffin-embedded, different stage breast cancer specimens were prepared and quantified for Bcl2L12 and Bcl2L12A expression by quantitative PCR. The correlation between Bcl2L12 and Bcl2L12A mRNA levels and clinicopathological characteristics was statistically analyzed. The results showed that Bcl2L12 and Bcl2L12A mRNA expression was not significantly distinctive across the different stage, grade and TNM classification groups, respectively (p=0.073, p=0.651; p=0.756, p=0.986; p=0.342, p=0.634). Using linear regression, Bcl2L12 mRNA was shown to be associated with Bcl2L12A mRNA expression, grade III tumor and the triple-negative breast cancer (TNBC) subtype (p<0.001; p=0.032; p=0.049). Bcl2L12A mRNA was positively associated with Bcl2L12 mRNA (p=0.003) and the number of lymph node metastases (p=0.018). However, in non-TNBC specimens, Bcl2L12 mRNA was only correlated with Bcl2L12A mRNA (p=0.001), and Bcl2L12A mRNA was significantly highly expressed in tumors with ≥12 metastatic lymph nodes (p=0.021). In summary, an elevated Bcl2L12 mRNA expression was associated with the high-grade BCa and TNBC subtype. In addition, the interplay between Bcl2L12 and its variant may be associated with high lymph node metastasis in non-TNBC tumors.

論文審定書………………………………………………………. i
誌謝 (Acknowledgements)……………………………………… ii
中文摘要(Abstract in Chinese)………………………………...… iii
英文摘要(Abstract in English)……………………………….…… iv-v
研究背景(Introduction)……………………………...……….……. 1-11
材料與方法(Material and Methods)………………………....… 12-20
結果(Results)……………………………………………...……..… 21-28
討論(Discussion)…………………………………………..……... 29-33
結論(Conclusion)………………………………………………...... 34
表(Tables)………………………………………………….……... 35-42
圖(Figures)…………………………………………….………….. 43-51
參考文獻(References)………………………………….……….. 52-58
附錄(Supplemental Data)………………………………………… 59

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