HLA‐G immune modulatory genes and molecules are presently being studied by a widespread number of research groups. In the present study, we do not aim to be exhaustive since the number of manuscripts published every year is overwhelming. Instead, our aim is pointing out facts about HLA‐G function, polymorphism and pathology that have been confirmed by several different researchers, together with exposing aspects that may have been overlooked or not sufficiently remarked in this productive field of study. On the other hand, we question whether performing mainly studies on HLA‐G and disease associations is going to give a clear answer in the future, since 40 years of study of classical HLA molecules association with disease has still given no definite answer on this issue.

Liver cirrhosis is a worldwide public health problem, and patients with this disease are at high risk of developing complications, bacterial translocation from the intestinal lumen to the mesenteric nodes, and systemic circulation, resulting in the development of severe complications related to high mortality rate. The intestinal barrier is a structure with a physical and biochemical activity to maintain balance between the external environment, including bacteria and their products, and the internal environment. Patients with liver cirrhosis develop a series of alterations in different components of the intestinal barrier directly associated with the severity of liver disease that finally increased intestinal permeability. A “leaky gut” is an effect produced by damaged intestinal barrier; alterations in the function of tight junction proteins are related to bacterial translocation and their products. Instead, increasing serum proinflammatory cytokines and hemodynamics modification, which results in the appearance of complications of liver cirrhosis such as hepatic encephalopathy, variceal hemorrhage, bacterial spontaneous peritonitis, and hepatorenal syndrome. The intestinal microbiota plays a fundamental role in maintaining the proper function of the intestinal barrier; bacterial overgrowth and dysbiosis are two phenomena often present in people with liver cirrhosis favoring bacterial translocation. Increased intestinal permeability has an important role in the genesis of these complications, and treating it could be the base for prevention and partial treatment of these complications.

HLA-G is a non-classical HLA class I molecule with immunomodulatory properties. It was initially described at the maternal-fetal interface, and it was later found that this molecule was constitutively expressed on certain immuneprivileged tissues, such as cornea, endothelial and erythroid precursors, and thymus. The immunosuppressive effect of HLA-G is exerted through the interaction with its cognate receptors, expressed on immunocompetent cells, like ILT2, expressed on NK, B, T cells and APCs; ILT4, on APCs; KIR, found on the surface of NK cells; and finally, the co-receptor CD8. Because of these immunomodulatory functions, HLA-G has been involved in several processes, amongst which organ transplantation, viral infections, cancer progression, and autoimmunity. HLA-G neo-expression on tumors has been recently described in several types of malignancies. In fact, tumor progression is tightly linked to the presence of the molecule, as it exerts its tolerogenic function, inhibiting the cells of the immune system and favoring tumor escape. Several polymorphisms in the 3’UTR region condition changes in HLA-G expression (14bp and +3142C/G, among others), which have been associated with both the development and outcome of patients with different tumor types. Also, in recent years, several studies have shown that HLA-G plays an important role in the control of autoimmune diseases. The ability of HLA-G to limit the progression of these diseases has been confirmed and, in fact, levels of the molecule and several of its polymorphisms have been associated with increased susceptibility to the development of autoimmune diseases, as well as increased disease severity. Thus, modulating HLA-G expression in target tissues of oncology patients or patients with autoimmune diseases may be potential therapeutic approaches to treat these pathological conditions.

Latin" rock scripts were discovered 30 years ago in Lanzarote and Fuerteventura Islands (Canary Islands). However, they are an incised linear writing which lacks Q, H, P and T frequent Latin letters and translation into Latin has not been possible. A transcription and a translation hypothesis was proposed long ago because scripts were almost identical to those of the Iberian semi-syllabary which was used in Iberia and France during first millennium BC; "Latin" scripts were named "Iberian-Guanche" and were mostly religious and funerary. This type of lineal incise writing is present in all seven Canary Islands and they may have been unnoticed because all other islands except Lanzarote and Fuerteventura are humid and covered by vegetation. This type of linear writings are, like Iberian, similar to Runes (Atlantic and Central Europe),Old Italian scripts (Raetian, Venetic, Lepontic, Etruscan) and Sitovo and Gradeshnistsa scripts (Bulgaria, 5 th millennium BC). Language behind Iberian-Guanche scripts might be related to both Berber and Old Basque languages. People who wrote "Iberian-Guanche" inscriptions seem to be Canary Island inhabitants and not visitors. Genes (people) of present and past Canary Islanders are difficult only to assign to North Africa because gene flow between North Africa and Iberia existed in prehistoric times and it is difficult to distinguish Iberian and North African with Canarian gene profiles. Genetics by itself is not sufficient for relating people or specific for geography, this is firmly demonstrated for mitochondrial genes. Linguistics, Culture, and Archaeology are necessary to interpret population genetics data. Extant pyramids in North Africa, Western Sahara and possibly Tenerife, existence of prehistoric artifacts and rock calendars ("Quesera"/Cheeseborad lunisolar calendar at Lanzarote and others at Gran Canaria Island) and presence of Cart-Ruts on Lanzarote volcano tops, may indicate an older date for Canarian prehistory than that of Punic/Roman presence. Finally Canarian prehistoric findings have been long neglected and forgotten but a common Iberian-Guanche rock writing culture existed in Canary Islands.

HLA-G is a non-classical class I HLA molecule that induces tolerance by acting on receptors of both innate and adaptive immune cells. When overexpressed in tumors, limits surveillance by the immune system. The HLA-G gene shows several polymorphisms involved in mRNA and protein levels. We decided to study the implication of two polymorphisms (rs371194629; 14bp INS/DEL and rs1063320; +3142 C/G) in paired tissue samples (tumoral and non-tumoral) from 107 Spanish patients with gastric adenocarcinoma and 58 healthy control individuals, to assess the possible association of the HLA-G gene with gastric adenocarcinoma susceptibility, disease progression and survival. The presence of somatic mutations involving these polymorphisms was also analyzed. The frequency of the 14bp DEL allele was increased in patients (70.0%) compared to controls (57.0%, p=0.025). In addition, the haplotype formed by the combination of the 14bp DEL/+3142 C variants is also increased in patients (54.1% vs 44.4%, p=0.034, OR=1.74 CI95% 1.05-2.89). Kaplan-Meier analysis revealed that 14bp DEL/DEL patients showed lower 5-year life-expectancy than INS/DEL or INS/INS (p=0.041). Adjusting for TNM staging (Cox regression analysis) disclosed a significant difference in death risk (p=0.03) with an expected hazard 2.6 times higher. Finally, no somatic mutations were found when comparing these polymorphisms in tumoral vs non-tumoral tissues, which indicates that this is a preexisting condition in patients and not a de novo, tumor-restricted, event. In conclusion, the variants predominant in patients were those increasing HLA-G mRNA stability and HLA-G expression, clearly involving this molecule in gastric adenocarcinoma susceptibility, disease progression and survival and making it a potential target for immunotherapeutic approaches.