CD24 and APC Genetic Polymorphisms in Pancreatic Cancers as Potential Biomarkers for Clinical Outcome

Position statement of the International Society for Gastrointestinal Hereditary Tumours (InSiGHT) on APC I1307K and cancer risk

While constitutional pathogenic variants in the APC gene cause familial adenomatous polyposis, APC c.3920T>A; p.Ile1307Lys (I1307K) has been associated with a moderate increased risk of colorectal cancer (CRC), particularly in individuals of Ashkenazi Jewish descent. However, published data include relatively small sample sizes, generating inconclusive results regarding cancer risk, particularly in non-Ashkenazi populations. This has led to different country/continental-specific guidelines regarding genetic testing, clinical management and surveillance recommendations for I1307K. A multidisciplinary international expert group endorsed by the International Society for Gastrointestinal Hereditary Tumours (InSiGHT), has generated a position statement on the APC I1307K allele and its association with cancer predisposition. Based on a systematic review and meta-analysis of the evidence published, the aim of this document is to summarise the prevalence of the APC I1307K allele and analysed the evidence of the associated cancer risk in different populations. Here we provide recommendations on the laboratory classification of the variant, define the role of predictive testing for I1307K, suggest recommendations for cancer screening in I1307K heterozygous and homozygous individuals and identify knowledge gaps to be addressed in future research studies. Briefly, I1307K, classified as pathogenic, low penetrance, is a risk factor for CRC in individuals of Ashkenazi Jewish origin and should be tested in this population, offering carriers specific clinical surveillance. There is not enough evidence to support an increased risk of cancer in other populations/subpopulations. Therefore, until/unless future evidence indicates otherwise, individuals of non-Ashkenazi Jewish descent harbouring I1307K should be enrolled in national CRC screening programmes for average-risk individuals.

Predictors of the CD24/CD11b Biomarker among Healthy Subjects

The CD24 gene has raised considerable interest in tumor biology as a new prognostic factor and a biomarker for the early detection of cancer. There are currently no studies that assess predictors of CD24 in blood tests among healthy individuals. Our aims were (1) to evaluate predictors of the CD24/CD11b biomarker among healthy subjects and (2) to assess CD24/CD11b levels of participants with and without benign tumors. Our cohort included 1640 healthy subjects, aged 20-85, recruited at the Health Promotion and Integrated Cancer Prevention Center (ICPC) in the Tel Aviv Medical Center. Eligible subjects completed a detailed questionnaire on medical history and other epidemiologic information. CD24/CD11b expression in peripheral blood leukocytes (PBLs) obtained from blood samples of participants was analyzed by flow cytometry. Our results showed that the average levels of CD24/CD11b in healthy patients (22.8 ± 9.3) was statistically significant lower compared to subjects with benign cancers (26.1 ± 10.5, p < 0.001). Our multivariable analysis demonstrated that elevated levels of CRP (coefficient β: 1.98, p = 0.011) were significantly associated with high levels of CD24/CD11b expression among healthy participants. Other risk factors of cancer were not associated with elevated CD24 levels among healthy subjects. In conclusion, our findings may assist in further development and optimization of the CD24/CD11b biomarker to serve as a cancer screening test for early detection of cancer among the healthy population.

CD24, A Review of its Role in Tumor Diagnosis, Progression and Therapy

CD24, is a mucin-like GPI-anchored molecules. By immunohistochemistry, it is widely detected in many solid tumors, such as breast cancers, genital system cancers, digestive system cancers, neural system cancers and so on. The functional roles of CD24 are either fulfilled by combination with ligands or participate in signal transduction, which mediate the initiation and progression of neoplasms. However, the character of CD24 remains to be intriguing because there are still opposite voices about the impact of CD24 on tumors. In preclinical studies, CD24 target therapies, including monoclonal antibodies, target silencing by RNA interference and immunotherapy, have shown us brighten futures on the anti-tumor application. Nevertheless, evidences based on clinical studies are urgently needed. Here, with expectancy to spark new ideas, we summarize the relevant studies about CD24 from a tumor perspective.

A Dinucleotide Deletion in the CD24 Gene Is a Potential Risk Factor for Colorectal Cancer

BACKGROUND

CD24 is a sialoglycoprotein anchored to the cell surface via glycosylphosphatidylinositol and is involved in intracellular signaling processes. It plays an important role in the early stages of the multistep process of colorectal carcinogenesis. Several single nucleotide polymorphisms in the CD24 gene are reported to exert a diverse effect on cancer risk. We aimed to elucidate whether CD24 TG/del genetic variants are associated with susceptibility to colorectal cancer (CRC).

METHODS

The study included 179 subjects, 36 with CRC (prior to surgery) and 143 healthy control subjects. Deoxyribonucleic acid was purified from peripheral blood leukocytes, and by using restriction fragment length polymorphism analysis, the CD24 gene was genotyped for the specific genetic variant, TG deletion. Additionally, CD24 protein expression levels were determined by Western blotting analysis.

RESULTS

The incidence of the TG/del was higher among the CRC patients compared with healthy controls, 14% and 10%, respectively (P = .54). CD24 protein levels were significantly higher among CRC patients. There were no significant differences in CD24 expression between CRC patients at different stages of the disease or between patients who carry the mutation and those who did not.

CONCLUSIONS

CD24 genetic variant might be of clinical value for risk assessment as part of cancer prevention programs. Further study on larger populations is needed to validate the importance of this dinucleotide deletion in CRC development. Overexpression of CD24 protein occurs early along the multistep process of CRC carcinogenesis, and a simple blood sample based on CD24 expression on peripheral blood leukocytes can contribute to early diagnosis.