LIDSEN series of journals are published by LIDSEN Publishing Inc, a non-profit scholarly Open Access publisher focused on biological, biomedical and medical studies. We aim to select ground-breaking research based on novelty, timeliness, scientific significance, potential audience interests, etc. We strive to provide an easily and freely accessible platform to researchers and practitioners in support of their novel and valuable ideas.

Insulin-like growth factor 2 (IGF2) is a strong mitogenic peptide with an imprinted gene that is primarily involved in fetal development. It is highly expressed in the fetus where it is involved in fetal growth and tissue differentiation. However, postnatally, the expression of IGF2 decreases despite higher expression levels in the blood as compared with that of IGF1. In adults, the physiological function of IGF2 is poorly understood; however, the possibility of a metabolic function exists. Although the expression of IGF2 normally decreases in adults, it is overexpressed in a variety of cancers and associated with increased insulin-like growth factor 1 (IGF1R) receptor and insulin receptor (IR) activity. This subsequently increases the activity of downstream genes such as <em>AKT</em>, <em>FOXO</em>, and <em>MAPK</em>, resulting in enhanced proliferation, survival, and overall worse prognosis in patients overexpressing IGF2. As IGF1R activation has been found in several types of cancers, many different IGF1R-targeted therapies have been clinically evaluated, however, with only limited anti-cancer efficacy. In the present review, the physiological function of IGF2 will be outlined in relation to gene expression, imprinting, and signaling. Additionally, differences in physiological and aberrant signaling of IGF2 in cancer will be summarized.

We present here the content and articles of this special issue on genetic screening, putting them in perspective with the field and between themselves.

Preimplantation Genetic Testing for HLA-matching (PGT-HLA) has been one of the most controversial PGT applications, first reported in 2001. The procedure aims to identify an embryo that is not only healthy but also HLA-matched with a sibling in the family in need of haematopoietic stem cell transplantation (HSCT), considering that sibling HSCT stands the highest chance of success in comparison to alternative approaches. HLA-typing can be performed with or without PGT-M for the exclusion of a single-gene disorder. The diagnostic PGT approach has greatly evolved over the years. HLA haplotyping by linkage analysis has been the most applied generic approach to date, but newer techniques (SNP arrays, NGS) have been applied recently. PGT-HLA is a complex procedure that must be very well orchestrated between specialists of many different disciplines to ensure that successful HSCT is completed on time. This review discusses the PGT procedure and methodology, PGT-HLA clinical application and utility and underlines how, despite the limitations, it has been a successful and realistic approach for many couples.

In order to successfully recover from damage, skeletal muscle tissue requires proper activation of a tightly orchestrated repair program. Non-coding RNAs actively participate in this complex process of demolition and rebuilding. In this review, the contribution of dysregulated non-coding RNA expression to disease-associated pathological changes is explored in hereditary muscular dystrophies and idiopathic inflammatory myopathies. Disturbances in spatiotemporal expression of non-coding RNAs appear to be key factors in disease progression, functioning both in favor of and opposed to recovery. They regulate regeneration and survival of muscle fibers as well as codetermine the severity of tissue fibrosis and inflammation. Non-coding RNAs display individual or pleiotropic effects, and strongly influence each other’s activities. The described altered expression patterns can be exploited as biomarkers for diagnosis and to evaluate therapeutic success. In addition, common signatures of these non-coding RNAs often present in different muscle disorders point to their manipulation as an approach for potentially broader therapeutic use.

Patients’ lay theories about the cause of their cancer may influence patient behavior and adjustment, they have also been found to differ substantially from scientific evidence of cancer risk factors. This report describes beliefs about genetic causes of breast cancer, among 522 recently diagnosed breast cancer survivors participating in an observational study. Patients were asked to respond to an open-ended question about the cause of their cancer. Causes mentioned included family history, genetics, lifestyle and exposure theories, often in combination. Of particular interest we found in total, 31% of women described inheritable causes, including family history, genetics, and specific genes. Lay theories about cancer’s cause appear to have evolved to include new information about breast cancer genetics including BRCA1/2, epigenetic influence, and other mutations. Other causes seen in prior reports are also described and were used in many cases in combination with genetic explanations. We present evidence that genetics and family history appear to be particularly satisfying answers to questions of cause for many women with breast cancer. These findings have implications for those seeking to educate and counsel breast cancer patients with and without a family history of cancer.

Pneumocystis jirovecii is an atypical fungus transmitted via interhuman airborn contact. This fungus is exclusively associated with humans and almost each individual has encountered it at least once before reaching the age of two. Pneumocystis jirovecii can be responsible for spontaneously resolutive symptoms in infants and for severe pneumocystis pneumonia (PCP) in immunocompromised patients. The increase of the population of immunocompromised patients would probably lead to rising of PCP infections in the next decades. With the advance of molecular technologies and Polymerase Chain Reaction (PCR) assays, the detection of low fungal load has been improved and several physiopathological questions has raised. For instance, is PCP due to reactivation of a colonizing strain or acquisition of a new one? Are the strains in PCP and non-PCP patients similar? Are outbreaks due to a specific strain? Most of these questions can be addressed using genotyping, which must be directly performed on clinical specimens because of the absence of reliable culture methods. In this review we will resume the main typing methods developed for P. jirovecii characterization, with their pros and cons, in insisting on the typing of the low fungal loads, a subject rarely underlined. Secondarily, we will present the main results obtained and the importance to include these patients with low fungal load in the analyses because of their possible role as reservoirs and their impact on P. jirovecii transmission. Eventually, we will open the debate on systematic treatment of the patients with low fungal load not only to prevent full-blown PCP, but also to block transmission chain.

Renal cysts are present in a wide variety of hereditary renal diseases in children. The term polycystic kidney disease (PKD) refers to two specific hereditary diseases, distinguished by the usual age of onset and genetic cause: autosomal recessive polycystic kidney disease/congenital hepatic fibrosis (ARPKD/CHF, MIM *606702) and autosomal dominant polycystic disease (ADPKD-OMIM *601313 and OMIM *173910). ARPKD/CHF is characterized by cystic dilations of the renal collecting ducts and developmental defects of biliary ductal plate remodeling, resulting in varying degrees of congenital hepatic fibrosis. ARPKD/CHF is commonly diagnosed <i>in utero </i>or at birth but can remain silent well into adolescence and rarely into adulthood. ADPKD, the most common inherited renal disease is characterized by slow, progressive enlargement of fluid-filled cysts leading to renal failure by the fifth to sixth decade of life in addition to various extrarenal manifestations. ADPKD can manifest in utero, infants, and children and can be a significant cause of morbidity and mortality in this age group. Our understanding of the genetic basis of ARPKD and ADPKD, including mechanisms of transmission and genes involved continues to evolve. Despite remarkable advances in understanding the basic molecular and cellular pathophysiology, the development of targeted therapies has proven difficult.

Histone modifications play an important role in the control of DNA-based processes by altering the structure and function of chromatin. <i>O</i>-linked N-acetylglucosamine (<i>O</i>-GlcNAc) modification is a form of post-translational modification of proteins that affects the serine (Ser)/threonine (Thr) residues. This process is controlled by a single pair of enzymes, i.e. <i>O</i>-GlcNAc transferase (OGT) and <i>O</i>-GlcNAcase (OGA). Recent evidence indicates the existence of <i>O</i>-GlcNAc modification of histones, with 16 histone <i>O</i>-GlcNAc sites reported to date. <i>O</i>-GlcNAc modification is a nutrient-sensitive modification; therefore, it is likely to serve as a molecular mechanism linking nutrient conditions and epigenetic status. Recently, functional analyses have been advanced by the acquisition of antibodies for the specific detection of <i>O</i>-GlcNAcylation of histone residues. Here, we discuss the current knowledge of histone <i>O-</i>GlcNAc modification, with a view to elucidating its comprehensive biological functions.