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CBX3/heterochromatin protein 1 gamma is significantly upregulated in patients with non–small cell lung cancer
Author(s) -
Chang ShihChieh,
Lai YiChun,
Chen YenChung,
Wang NaiKuan,
Wang WeiShu,
Lai JiunI
Publication year - 2018
Publication title -
asia‐pacific journal of clinical oncology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 29
eISSN - 1743-7563
pISSN - 1743-7555
DOI - 10.1111/ajco.12820
Subject(s) - lung cancer , downregulation and upregulation , heterochromatin protein 1 , immunohistochemistry , cancer research , biology , heterochromatin , tissue microarray , pathology , medicine , oncology , gene , genetics , chromatin
Aim Lung cancer is typically categorized into small cell lung cancer (SCLC) and non–small cell lung cancer (NSCLC). NSCLC comprises of the majority of lung cancer with a poor prognosis in advanced cases. Transcriptional profiling studies, including microarrays and RNA‐sequencing studies, have significantly enriched our knowledge of gene expression patterns in NSCLC. A recent transcriptional profiling study identified high prevalence of CBX3 /HP1‐gamma upregulation in human NSCLC samples. CBX3 /HP1‐gamma is an isoform of the heterochromatin protein 1 family, which plays a role in heterochromatin formation and is linked to cancer. Methods We examined lung cancer samples from our hospital using immunohistochemistry for CBX3 /HP1‐gamma staining. We also analyzed publicly available databases of NSCLC transcriptional profiling to validate our results. Results We identified a high prevalence (77.2%) of samples with positive CBX3/HP1‐gamma staining by immunohistochemistry in NSCLC patient samples. Independently, we queried a publicly available dataset (GSE40419) containing RNA‐seq data from 77 patients. Upregulation of CBX3 /HP1‐gamma in tumor samples was present in 60.2% of the patients. A similar correlation was also observed in the The Cancer Genome Atlas (TCGA) database. Interestingly, we discovered a highly significant association between positive CBX3 /HP1‐gamma staining and EGFR mutation in our patient samples (40 of 42 patients, P < 0.001). Treatment of EGFR mutant NSCLC cell lines with the EGFR inhibitor gefitinib failed to yield a change in CBX /HP1‐gamma expression, suggesting that CBX /HP1‐gamma expression may be independent of EGFR downstream signaling. Conclusion We report a significant upregulation of CBX3 /HP1‐gamma in NSCLC patients, and also a possible relationship between CBX3 /HP1‐gamma expression and EGFR mutation.