Supplementary Material for: Cytogenetic Profile Of Acute Lymphoblastic Leukaemia in South India: A Series Of 1819 Patients From A Single Centre

Introduction: Cytogenetic findings are critical for determining prognosis, therapy and risk assessment in acute lymphoblastic leukaemia (ALL). Data on the epidemiology of cytogenetic findings in ALL from southern Asia is limited. This report documents the cytogenetic changes in ALL seen at a referral hospital in southern India and compares it with the literature.
Methods: Clinical profiling and conventional cytogenetic analysis (CCA) of all patients with reverse-transcription polymerase chain reaction (RT-PCR) for detection of cryptic t(12;21).
Results: Of 1968 ALL, 1,819 (92.4%) patients, age 0.3-84 years, (median 17) had successful CCA. There were 979 children (<18 years) and 840 adults. Abnormal karyotypes were found in 1368 (75.2%), B-ALL-78% and T-ALL-69%.
Favorable-risk group included high hyperdiploidy (HeH, 17.4%), t(12;21) (9.8%), and t(1;19) (4.3%), with > 80% of HeH and t(12;21) in children. The unfavorable-risk group included t(9;22) (11.2%, 80% adults), hypodiploidy (8.0%), MYC (8q24) translocations (2.3%), and KMT2A/MLL(11q23) translocations (1.6%).
In children, the frequency of HeH (26.8%) was lower than the West (30.7%) but higher than S.E. Asia (15.5%) while t(9;22) (4.2%) was higher than the West (2%) but lower than S.E. Asia (6.8%). In adults, frequencies again differed from S.E. Asia (HeH, 6.4% vs. 2.7% and t(9;22), 19.4% vs. 29.3%) but were comparable to the West.
Conclusion: CCA effectively provides diagnostic information in over 90% of ALL cases. While the spectrum of cytogenetic changes is similar to global data, there are significant regional variations in the frequencies of specific abnormalities.

背景：细胞遗传学检测结果对于急性淋巴细胞白血病（Acute Lymphoblastic Leukaemia, ALL）的预后判定、治疗方案选择及风险评估具有关键意义。目前南亚地区关于ALL细胞遗传学检测结果的流行病学数据较为匮乏。本研究记录了印度南部一家转诊医院收治的ALL患者的细胞遗传学改变情况，并与现有文献进行了对比分析。
方法：对所有接受逆转录聚合酶链反应（reverse-transcription polymerase chain reaction, RT-PCR）检测隐匿性t(12;21)易位的患者进行临床特征分析及常规细胞遗传学分析（conventional cytogenetic analysis, CCA）。
结果：在1968例ALL患者中，共计1819例（92.4%）患者成功完成常规细胞遗传学分析，年龄范围为0.3~84岁，中位年龄17岁，其中儿童患者（<18岁）979例，成人患者840例。核型异常检出率为75.2%（1368例），其中B细胞型ALL（B-ALL）占比78%，T细胞型ALL（T-ALL）占比69%。
预后良好组包括超高二倍体（high hyperdiploidy, HeH，占比17.4%）、t(12;21)易位（占比9.8%）以及t(1;19)易位（占比4.3%），其中超过80%的HeH与t(12;21)易位病例见于儿童患者。预后不良组包括t(9;22)易位（占比11.2%，其中80%为成人患者）、低二倍体（占比8.0%）、MYC（8q24）易位（占比2.3%）以及KMT2A/MLL（11q23）易位（占比1.6%）。
在儿童患者中，HeH检出率（26.8%）低于西方人群（30.7%），但高于东南亚地区（15.5%）；而t(9;22)易位检出率（4.2%）高于西方人群（2%），但低于东南亚地区（6.8%）。在成人患者中，各项检出率与东南亚地区存在差异（HeH：6.4% vs 2.7%；t(9;22)易位：19.4% vs 29.3%），但与西方人群数据相当。
结论：常规细胞遗传学分析可在超过90%的ALL病例中提供有效的诊断信息。尽管ALL细胞遗传学改变的整体谱与全球数据基本一致，但特定异常的检出率存在显著的区域差异。