Deriving benefit of early detection from biomarker-based prognostic models

Genetic variants in RNA m5 C modification genes associated with survival and chemotherapy efficacy of colorectal cancer

BACKGROUND

Colorectal cancer is one of the most common malignant digestive tract tumors with a poor prognosis. RNA 5-methylcytosine (m⁵ C) is an important posttranscriptional widespread modification involved in many biological processes. However, the association between genetic variations of m⁵ C modification genes and the prognostic value of colorectal cancer remains unclear.

METHODS

We investigated the association between candidate single nucleotide polymorphisms (SNPs) in 13 m⁵ C modification genes and colorectal cancer overall survival (OS) after chemotherapy by the Cox regression model. The combined effect of selected SNPs on OS, progression-free survival (PFS), and disease control rate (DCR) was assessed by the number of risk alleles (NRA). The GTEx and TCGA database were used to perform expression qualitative trait locus (eQTL) analysis.

RESULTS

We identified that two SNPs in YBX1 were associated with OS after chemotherapy (HR = 1.43, p = 0.001 for rs10890208; HR = 1.36, p = 0.025 for rs3862218). A striking dose-response effect between NRA and OS after chemotherapy was found (p_trend  = 0.002). The DCR of patients receiving oxaliplatin chemotherapy in the 3-4 NRA group was markedly reduced in comparison to that in the 0-2 NRA group (OR = 1.49, p = 0.036). Moreover, YBX1 mRNA expression was significantly overexpressed in tumor tissues (p < 0.05) in the TCGA database, and eQTL analysis demonstrated that the two SNPs were associated with YBX1 (p = 0.003 for rs10890208 and p = 0.024 for rs3862218).

CONCLUSION

Our study indicates that genetic variants in m⁵ C modification genes may mediate changes in YBX1 mRNA levels and affect the chemotherapeutic efficacy of colorectal cancer patients.

Identification of LEA, a podocalyxin-like glycoprotein, as a predictor for the progression of colorectal cancer

Large external antigen (LEA) is considered as a colorectal cancer (CRC)‐associated antigen, which was found via mAb ND‐1 generated using hybridoma technology, but its molecular features remain unknown. To facilitate the clinical application of LEA, we identified LEA as a podocalyxin‐like protein 1 (PODXL) with molecular weight of approximately 230 kDa, a hyperglycosylated protein, using immunoprecipitation and mass spectrometry in combination, and verified that ND‐1‐recognized epitope is on the terminal sialic acid of LEA. Correlation analysis between LEA and PODXL in molecular weight, immunological cross‐reactivity, and gene expression dependence supported the PODXL identity of the LEA. Moreover, we assessed the clinical significance of the LEA in 89 pairs of primary CRC tissues and adjacent nontumor colorectal tissues using ND‐1 by quantum dot‐based immunohistochemistry (QD‐IHC). High LEA expression was correlated significantly with T stage (P = 0.010). Patients with high LEA expression showed significantly poorer prognosis than those with LEA low expression (P = 0.007). Multivariate analysis indicated LEA expression as an independent predictor. Furthermore, the comparative analysis showed that mAb ND‐1‐based IHC analysis toward sugar residue of PODXL has higher sensitivity and specificity to evaluate the LEA/PODXL expression than mAb 3D3‐based method toward core protein of PODXL in CRC cell lines and clinical samples. In addition, we first found that LEA/PODXL can be secreted in exosomes from cancer cells and CRC patient peripheral blood. Our results demonstrate that LEA is an independent predictor for CRC progression and has the potential to be applied for clinical setting with high sensitivity, high specificity, and noninvasive access.

Comparative Analysis of Biopsy Upgrading in Four Prostate Cancer Active Surveillance Cohorts

BACKGROUND

Active surveillance (AS) is increasingly accepted for managing low-risk prostate cancer, yet there is no consensus about implementation. This lack of consensus is due in part to uncertainty about risks for disease progression, which have not been systematically compared or integrated across AS studies with variable surveillance protocols and dropout to active treatment.

OBJECTIVE

To compare risks for upgrading from a Gleason score (GS) of 6 or less to 7 or more across AS studies after accounting for differences in surveillance intervals and competing treatments and to evaluate tradeoffs of more versus less frequent biopsies.

DESIGN

Joint statistical model of longitudinal prostate-specific antigen (PSA) levels and risks for biopsy upgrading.

SETTING

Johns Hopkins University (JHU); Canary Prostate Active Surveillance Study (PASS); University of California, San Francisco (UCSF); and University of Toronto (UT) AS studies.

PATIENTS

2576 men aged 40 to 80 years with a GS between 2 and 6 and clinical stage T1 or T2 prostate cancer enrolled between 1995 and 2014.

MEASUREMENTS

PSA levels and biopsy GSs.

RESULTS

After variable surveillance intervals and competing treatments were accounted for, estimated risks for biopsy upgrading were similar in the PASS and UT studies but higher in UCSF and lower in JHU studies. All cohorts had a delay of 3 to 5 months in detecting upgrading with biennial biopsies starting after a first confirmatory biopsy versus annual biopsies.

LIMITATION

The model does not account for possible misclassification of biopsy GS.

CONCLUSION

Men in different AS studies have different risks for biopsy upgrading after variable surveillance protocols and competing treatments are accounted for. Despite these differences, the consequences of more versus less frequent biopsies seem to be similar across cohorts. Biennial biopsies seem to be an acceptable alternative to annual biopsies.

PRIMARY FUNDING SOURCE

National Cancer Institute.

Serum vascular adhesion protein-1 predicts all-cause mortality and cancer-related mortality in subjects with colorectal cancer

BACKGROUND

Vascular adhesion protein-1 (VAP-1) participates in inflammation and catalyzes the breakdown of amines to produce aldehyde, hydrogen peroxide, and ammonia. Serum VAP-1 can predict cancer mortality, including colorectal cancer (CRC) mortality, in type 2 diabetic subjects. However, it remains unknown if serum VAP-1 can predict mortality in CRC patients. This prospective cohort study investigates if serum VAP-1 is a novel biomarker for mortality prediction in CRC.

METHODS

We enrolled 300 CRC patients. Preoperative serum VAP-1 was measured by time-resolved immunofluorometric assay. They were followed until September 2009 or death, which was ascertained by the National Death Registration System.

RESULTS

The median follow-up period was 4.7 years. Compared with normal counterpart, VAP-1 immunoactivity was upregulated in CRC tissues, especially at the invasion front. Serum VAP-1 can independently predict all-cause mortality (HR: 1.0026, 95% CI: 1.0003-1.0050, P<0.05) and cancer-related mortality (HR: 1.0026, 95% CI: 1.0001-1.0050, P<0.05). A risk score composed of age, gender, carcinoembryonic antigen (CEA) >5 ng/ml, tumor grading, tumor staging, and serum VAP-1 could stratify CRC patients into low-, intermediate-, and high-risk subgroups, with a 5-year mortality rate of 10%, 34%, and 78%, respectively.

CONCLUSIONS

Serum VAP-1 predicts mortality independently and improves risk stratification in CRC subjects.