Molecular methods for colorectal cancer screening:Progress with next-generation sequencing evolution

Currently,colorectal cancer(CRC)represents the third most common malignancy and the second most deadly cancer worldwide,with a higher incidence in developed countries.Like other solid tumors,CRC is a heterogeneous genomic disease in which various alterations,such as point mutations,genomic rearrangements,gene fusions or chromosomal copy number alterations,can contribute to the disease development.However,because of its orderly natural history,easily accessible onset location and high lifetime incidence,CRC is ideally suited for preventive intervention,but the many screening efforts of the last decades have been compromised by performance limitations and low penetrance of the standard screening tools.The advent of next-generation sequencing(NGS)has both facilitated the identification of previously unrecognized CRC features such as its relationship with gut microbial pathogens and revolutionized the speed and throughput of cataloguing CRC-related genomic alterations.Hence,in this review,we summarized the several diagnostic tools used for CRC screening in the past and the present,focusing on recent NGS approaches and their revolutionary role in the identification of novel genomic CRC characteristics,the advancement of understanding the CRC carcinogenesis and the screening of clinically actionable targets for personalized medicine.

Evaluation of the impact of leucocytospermia on semen oxidative status by chemiluminescence technique in infertile men

The presence of high reactive oxygen species (ROS) levels in semen is a major factor involved in the decline of male fertility. In seminal plasma, ROS are mainly produced by activated leucocytes. Spermatozoa were the first cell type reported to show a potential susceptibility to oxidative damage. The aim of our study was to evaluate the impact of leucocytospermia on basal and FMLP (Formyl-Methionyl-Leucyl-Phenylalanine) induced oxidative status in semen of infertile men. We also analyzed the correlations of the spermatic parameters with amounts of ROS in semen. Our study included 50 semen samples of infertile men. Sperm analysis was performed using WHO standardized method. Seminal leucocytes were quantified using peroxidase technique. The measurement of ROS levels in semen was made by chemiluminescence assay. We measure respectively ROS amounts in neat semen and in washed sperm cells suspension from the same ejaculate. We also applied the test of provocation of leucocytes by FMLP on neat and washed samples to assess the spermatic oxidative status after leucocyte stimulation. Our results showed significant correlations between ROS levels in neat semen and many sperm parameters: motility, sperm concentration, leucocytes concentration and the rate of sperm cytoplasmic droplets. The studied samples were divided into 2 groups: (G1) composed of 36 samples without leucocytospermia and (G2) composed of 14 leucospermic samples. ROS levels were significantly lower in G1 than in G2 (p = 0.002). ROS production was significantly increased after application of FMLP in washed leucospermic samples (p = 0.001). The measurement of ROS in neat semen is a considerable contribution to explore the impairment of semen quality in infertile men. ROS levels in washed semen reflect the oxidative status generated by sperm preparation techniques used in assisted reproductive procedures. Levels of ROS are highly influenced by the presence of leucocytes and associated with decreased seminal parameters.

Genetic causes of macrozoospermia and proposal for an optimized genetic diagnosis strategy based on sperm parameters

Macrozoospermia,characterized by the presence of largeheaded spermatozoa usually carrying several flagella,is one of the most severe phenotypes of male infertility.As in most cases,the gametes are chromosomally abnormal and cannot be used for assisted reproductive technologies(ART)(Ray et al.,2017).In 2007,subjects from consanguineous families were shown to carry the same homozygous deleterious AURKC variant(NM_001015878.2:c.144delC,later renamed c.145delC,p.Leu49TrpfsTer23),establishing AURKC as the first and main gene associated with macrozoospermia(Dieterich et al.,2007).Using flow cytometry,all spermatozoa from patients homozygous for the c.145delC variant were shown to be tetraploid,highlighting a cytokinesis blockage of the first meiotic divisions thus confirming that ART cannot be successful for these patients(Dieterich et al.,2009).