Touch imprint cytology with massively parallel sequencing (TIC-seq): a simple and rapid method to snapshot genetic alterations in tumors.
Kenji AmemiyaYosuke HirotsuTaichiro GotoHiroshi NakagomiHitoshi MochizukiToshio OyamaMasao OmataPublished in: Cancer medicine (2016)
Identifying genetic alterations in tumors is critical for molecular targeting of therapy. In the clinical setting, formalin-fixed paraffin-embedded (FFPE) tissue is usually employed for genetic analysis. However, DNA extracted from FFPE tissue is often not suitable for analysis because of its low levels and poor quality. Additionally, FFPE sample preparation is time-consuming. To provide early treatment for cancer patients, a more rapid and robust method is required for precision medicine. We present a simple method for genetic analysis, called touch imprint cytology combined with massively paralleled sequencing (touch imprint cytology [TIC]-seq), to detect somatic mutations in tumors. We prepared FFPE tissues and TIC specimens from tumors in nine lung cancer patients and one patient with breast cancer. We found that the quality and quantity of TIC DNA was higher than that of FFPE DNA, which requires microdissection to enrich DNA from target tissues. Targeted sequencing using a next-generation sequencer obtained sufficient sequence data using TIC DNA. Most (92%) somatic mutations in lung primary tumors were found to be consistent between TIC and FFPE DNA. We also applied TIC DNA to primary and metastatic tumor tissues to analyze tumor heterogeneity in a breast cancer patient, and showed that common and distinct mutations among primary and metastatic sites could be classified into two distinct histological subtypes. TIC-seq is an alternative and feasible method to analyze genomic alterations in tumors by simply touching the cut surface of specimens to slides.
Keyphrases
- circulating tumor
- obsessive compulsive disorder
- cell free
- single molecule
- single cell
- genome wide
- fine needle aspiration
- gene expression
- small cell lung cancer
- squamous cell carcinoma
- rna seq
- copy number
- high grade
- nucleic acid
- cancer therapy
- dna methylation
- circulating tumor cells
- mass spectrometry
- ultrasound guided
- big data
- molecularly imprinted
- quality improvement
- electronic health record
- combination therapy