肿瘤病人多位点取样也可以结合450K芯片
前面介绍的大量研究都是对肿瘤病人进行多位点取样做NGS，也通常是WES
而 Oncotarget. 2017 Mar 文章不一样：
we generated methylation profiles of 48 spatially separated tumor regions from 11 localized lung adenocarcinomas and their matched normal lung tissues using Illumina Infinium Human Methylation 450K BeadChip array.
作者并没有给出原始数据。
然后本研究是 11 个病人，在作者前面的文章里面探索过其 SNV, CNV 的异质性。
另外一篇2014文章, Intratumor DNA Methylation Heterogeneity Reflects Clonal Evolution in Aggressive Prostate Cancer 倒是有原始数据：Illumina 450K arrays reported in this paper is EGAS00001000682. 但是也需要申请才能下载。
A total of five prostate cancer patients were selected that had large unifocal prostate cancers, adjacent high-grade PIN that was large enough to be separately analyzed, and at least three nodal metastases measuring ≥1 cm.
也就是说总共的5个病人，采样包括：
multiple geographically distinct primary tumor sites (TU; n = 10)
premalignant lesions (PIN; n = 2)
lymph node metastases (LNM; n = 3)
matched normal prostate epithelium (NP; n = 1)