Apolipoprotein C1(APOC1) is overexpressed in primary colorectal cancer (CRC).
Notes: (A) APOC1 was highly expressed in CRC (n=380) samples compared to adjacent normal (n=50) samples based on The Cancer Genome Atlas (TCGA) database (unpaired t-test, P=0.012). (B) APOC1 was highly expressed in colorectal cancer samples compared to the adjacent normal samples of a matched paired group (n=25) based on The Cancer Genome Atlas (TCGA) database (paired t-test, P=0.002). (C) The mRNA expression level of APOC1 was higher in the majority of the 15 colorectal cancer tissues compared with the matched adjacent normal tissues (paired t-test, P<0.01). (D) The protein expression level of APOC1 was detected by Western blotting. Protein expression was higher in the colorectal cancer tissues (T1-T4) compared with the matched adjacent normal tissues (N1-N4). (E) Immunohistochemical detection of APOC1 protein expression in paraffin-embedded tissues. Positive APOC1 staining was observed mainly in the cytoplasm of CRC tissues; a and e, APOC1 was not detected in normal colorectal tissues; b and f, representative images of weak APOC1 staining in CRC tissues; c and g, representative images of moderate APOC1 staining in CRC tissues; d and h, representative images of strong APOC1 staining in CRC tissues; a, b, c, and d, original magnification ×100 (scale bar =100 μM); e, f, g, and h, ×400. (F) and (G) Kaplan–Meier survival analysis according to APOC1 expression in 140 patients with CRC. The overall survival (OS) and disease-free survival (DFS) for patients with high versus low APOC1 expression. The difference is statistically significant based on the log-rank test (both P<0.001).