Colorectal cancer (CRC) is one of the main causes of death of neoplasia. Demand for predictive and prognostic markers to reverse this trend is increasing. Long non-coding RNA HOTAIR (Homeobox Transcript Antisense Intergenic RNA) overexpression in tumors was previously associated with poor prognosis and higher mortality in different carcinomas. We analyzed HOTAIR expression levels in tumor and blood of incident sporadic CRC patients in relation to their overall survival with the aim to evaluate surrogate prognostic marker for CRC. Tissue donor group consisted of 73 CRC patients sampled for tumor and normal tissue. Blood donor group was represented by 84 CRC patients compared with 40 healthy controls. Patients were characterized for tumor-node-metastasis stage, tumor grade, microsatellite instability and tumor penetration by stromal cells. HOTAIR levels were assessed by real-time quantitative PCR. CRC patients had higher HOTAIR expression in blood than healthy controls (P = 0.0001), whereas there was no difference in HOTAIR levels between tumor and adjacent mucosa of CRC patients. HOTAIR levels positively correlated between blood and tumor (R = 0.43, P = 0.03). High HOTAIR levels in tumors were associated with higher mortality of patients [Cox's proportional hazard, hazard ratio = 4.4, 95% confidence interval: 1.0-19.2, P = 0.046]. The hazard ratio was even higher when blood HOTAIR levels were taken into account (hazard ratio = 5.9, 95% confidence interval: 1.3-26.1, P = 0.019). Upregulated HOTAIR relative expression in primary tumors and in blood of CRC patients is associated with unfavorable prognosis. Our data suggest that HOTAIR blood levels may serve as potential surrogate prognostic marker in sporadic CRC.

Germline mutations in checkpoint kinase 2 (CHEK2), a multiple cancer‐predisposing gene, increase breast cancer (BC) risk; however, risk estimates differ substantially in published studies. We analyzed germline CHEK2 variants in 1,928 high‐risk Czech breast/ovarian cancer (BC/OC) patients and 3,360 population‐matched controls (PMCs). For a functional classification of VUS, we developed a complementation assay in human nontransformed RPE1‐CHEK2‐knockout cells quantifying CHK2‐specific phosphorylation of endogenous protein KAP1. We identified 10 truncations in 46 (2.39%) patients and in 11 (0.33%) PMC (p = 1.1 × 10−14). Two types of large intragenic rearrangements (LGR) were found in 20/46 mutation carriers. Truncations significantly increased unilateral BC risk (OR = 7.94; 95%CI 3.90–17.47; p = 1.1 × 10−14) and were more frequent in patients with bilateral BC (4/149; 2.68%; p = 0.003), double primary BC/OC (3/79; 3.80%; p = 0.004), male BC (3/48; 6.25%; p = 8.6 × 10−4), but not with OC (3/354; 0.85%; p = 0.14). Additionally, we found 26 missense VUS in 88 (4.56%) patients and 131 (3.90%) PMC (p = 0.22). Using our functional assay, 11 variants identified in 15 (0.78%) patients and 6 (0.18%) PMC were scored deleterious (p = 0.002). Frequencies of functionally intermediate and neutral variants did not differ between patients and PMC. Functionally deleterious CHEK2 missense variants significantly increased BC risk (OR = 3.90; 95%CI 1.24–13.35; p = 0.009) and marginally OC risk (OR = 4.77; 95%CI 0.77–22.47; p = 0.047); however, carriers low frequency will require evaluation in larger studies. Our study highlights importance of LGR detection for CHEK2 analysis, careful consideration of ethnicity in both cases and controls for risk estimates, and demonstrates promising potential of newly developed human nontransformed cell line assay for functional CHEK2 VUS classification.

Purpose: DNA repair capacity (DRC) is a determinant not only of cancer development but also of individual response to therapy. Previously, altered base and nucleotide excision repair (BER and NER) have been described in lymphocytes of patients with sporadic colorectal cancer. We, for the first time, evaluate both excision repair capacities in human colon biopsies to study their participation in colorectal tumorigenesis.Experimental design: Seventy pairs of tumor and adjacent healthy tissues were analyzed for BER-and NER-specific DRC by a comet repair assay. Tissue pairs were further compared for expression levels of a panel of 25 BER and NER genes complemented by their promoter methylation status.