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Q1. Please select the correct descriptions about diffuse large B-cell lymphoma (DLBCL):

(1) Patients with germinal center B-cell-like (GCB) DLBCL have better prognosis than active B-cell-like (ABC) DLBCL. (2) Activated B-cell receptor and NF-κB signaling are hallmarks of ABC-type DLBCL. (3) EZH2 mutation is enriched in GCB-type DLBCL. (4) Double-hit DLBCL is more common in ABC-type DLBCL and linked to poor prognosis.

  • (A) 1
  • (B) 1+3
  • (C) 2+4
  • (D) 1+2+3
  • (E) 1+2+3+4
點此顯示正解

(D) 1+2+3

詳解

Analysis

The stem asks to "select the correct descriptions" about DLBCL, meaning we are looking for the TRUE statements. The slide-marked answer is (D) 1+2+3, indicating that statements 1, 2, and 3 are correct, while statement 4 is incorrect.

Why (D) is the Correct Answer

Option (D) correctly identifies statements 1, 2, and 3 as true while excluding statement 4, which is false.

Statement (1) is TRUE: Patients with GCB DLBCL have better prognosis than ABC DLBCL. The ABC subtype has inferior outcomes with 3-year progression-free survival of approximately 40-50% versus 75% for the GCB subtype1. Multiple sources confirm that GCB-type DLBCL displays a more favorable outcome after standard chemotherapy compared to ABC-type3[^7].

Statement (2) is TRUE: Activated B-cell receptor and NF-κB signaling are hallmarks of ABC-type DLBCL. The ABC subtype is characterized by chronic B-cell receptor signaling and activation of nuclear factor κB1. Constitutive NF-κB activation is the hallmark of ABC DLBCL and likely contributes to its resistance to immunochemotherapy2. The ABC subgroup expresses genes characteristic of blood B-cells that have been acutely stimulated through the BCR, notably including many NF-κB target genes2.

Statement (3) is TRUE: EZH2 mutation is enriched in GCB-type DLBCL. The GCB subtype expresses genes commonly detected in germinal center B cells, including BCL6 and EZH21. The genetic subtype termed "EZB" (based on EZH2 mutations and BCL2 translocations) is associated with favorable survival and represents a GCB-associated genetic pattern5.

Statement (4) is FALSE: Double-hit DLBCL is NOT more common in ABC-type DLBCL. In fact, double-hit lymphomas are usually detected in GCB-type DLBCL3[^7]. High-grade B-cell lymphoma with MYC and BCL2 rearrangements occurs in the majority of cases with the GCB subtype, in which BCL2 rearrangements occur exclusively[^8]. Double-hit lymphomas are typically GCB, while double-expressor lymphomas (which show co-expression by immunohistochemistry without translocations) are most often of the ABC subtype[9][11]. While the poor prognosis association is correct, the cell-of-origin association is wrong.

Why the Other Options Are Incorrect

(A) 1 only: This option includes only statement 1 (true) but excludes statements 2 and 3, which are also true. Therefore, it is incomplete.

(B) 1+3: This option includes statements 1 and 3 (both true) but excludes statement 2, which is also true. Therefore, it is incomplete.

(C) 2+4: This option includes statement 2 (true) but also includes statement 4, which is false. Statement 4 incorrectly states that double-hit DLBCL is more common in ABC-type when it is actually more common in GCB-type.

(E) 1+2+3+4: This option includes all four statements, but statement 4 is false. Double-hit lymphomas are predominantly GCB-type, not ABC-type3[7][8][^9].

詳解 · 中文翻譯

分析

題目要求「選擇正確的敘述」關於 DLBCL，意思是尋找真實的陳述。幻燈片標記的答案是 (D) 1+2+3，表示敘述 1、2 和 3 是正確的，而敘述 4 是錯誤的。

為什麼 (D) 是正確答案

選項 (D) 正確地將敘述 1、2 和 3 識別為真實，同時排除敘述 4，其為假。

敘述 (1) 為真：GCB DLBCL 患者的預後優於 ABC DLBCL。ABC 亞型的預後較差，3 年無進展生存期約為 40-50%，而 GCB 亞型約為 75%1。多個來源證實，在標準化療後，GCB 型 DLBCL 顯示比 ABC 型更有利的結果3[^7]。

敘述 (2) 為真：活化 B 細胞受體和 NF-κB 信號傳導是 ABC 型 DLBCL 的特徵。ABC 亞型的特徵是 B 細胞受體信號的長期激活和核因子 κB 的活化1。本構型 NF-κB 激活是 ABC DLBCL 的特徵，可能促進其對免疫化療的耐藥性2。ABC 亞群表達血液 B 細胞通過 BCR 急性刺激後的特徵基因，特別是包括許多 NF-κB 靶基因2。

敘述 (3) 為真：EZH2 突變在 GCB 型 DLBCL 中富集。GCB 亞型表達通常在生髮中心 B 細胞中檢測到的基因，包括 BCL6 和 EZH21。稱為「EZB」的遺傳亞型（基於 EZH2 突變和 BCL2 易位）與良好的生存相關，代表 GCB 相關的遺傳模式5。

敘述 (4) 為假：雙打擊 DLBCL 不是在 ABC 型 DLBCL 中更常見。事實上，雙打擊淋巴瘤通常在 GCB 型 DLBCL 中檢測到3[^7]。具有 MYC 和 BCL2 易位的高級 B 細胞淋巴瘤在大多數 GCB 亞型病例中出現，在其中 BCL2 易位專門出現[^8]。雙打擊淋巴瘤通常為 GCB 型，而雙表達淋巴瘤（在免疫組織化學中顯示共表達但無易位）最常見的是 ABC 亞型[9][11]。雖然預後不佳的關聯是正確的，但細胞來源關聯是錯誤的。

為什麼其他選項是不正確的

(A) 僅 1：此選項僅包括敘述 1（真實）但排除敘述 2 和 3，兩者也是真實的。因此，它是不完整的。

(B) 1+3：此選項包括敘述 1 和 3（都是真實），但排除敘述 2，其也是真實的。因此，它是不完整的。

(C) 2+4：此選項包括敘述 2（真實）但也包括敘述 4，其為假。敘述 4 不正確地指出雙打擊 DLBCL 在 ABC 型中更常見，而它實際上在 GCB 型中更常見。

(E) 1+2+3+4：此選項包括所有四個敘述，但敘述 4 是假的。雙打擊淋巴瘤主要是 GCB 型，不是 ABC 型3[7][8][^9]。

參考文獻 (AMA)

  1. Sehn LH, Salles G. Diffuse Large B-Cell Lymphoma. The New England Journal of Medicine. 2021;384(9):842-858. doi:10.1056/NEJMra2027612. PMID:33657296. ↩↩↩↩↩↩

  2. Silkenstedt E, Salles G, Campo E, Dreyling M. B-Cell Non-Hodgkin Lymphomas. Lancet (London, England). 2024;403(10438):1791-1807. doi:10.1016/S0140-6736(23)02705-8. PMID:38614113. ↩↩↩↩

  3. Young RM, Phelan JD, Wilson WH, Staudt LM. Pathogenic B-Cell Receptor Signaling in Lymphoid Malignancies: New Insights to Improve Treatment. Immunological Reviews. 2019;291(1):190-213. doi:10.1111/imr.12792. PMID:31402495. ↩↩↩↩↩↩

  4. Schmitz R, Wright GW, Huang DW, et al. Genetics and Pathogenesis of Diffuse Large B-Cell Lymphoma. The New England Journal of Medicine. 2018;378(15):1396-1407. doi:10.1056/NEJMoa1801445. PMID:29641966. ↩

  5. Bisso A, Sabò A, Amati B. MYC in Germinal Center-Derived Lymphomas: Mechanisms and Therapeutic Opportunities. Immunological Reviews. 2019;288(1):178-197. doi:10.1111/imr.12734. PMID:30874346. ↩↩

  6. Liu Y, Barta SK. Diffuse Large B-Cell Lymphoma: 2019 Update on Diagnosis, Risk Stratification, and Treatment. American Journal of Hematology. 2019;94(5):604-616. doi:10.1002/ajh.25460. PMID:30859597. ↩

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