Association of CTLA-4 (AT)n Variants in Basal Cell Carcinoma and Squamous Cell Carcinoma Patients from Western Mexico.

The incidence of basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) is constantly increasing, becoming a significant health problem. CTLA-4 is a critical immune checkpoint, and it has been suggested that a variant of variable-number tandem repeat in the 3'-UTR of its gene, known as (AT)n, may be associated with a higher susceptibility to some cancers; however, little is known about genetic variants of the CTLA-4 gene in NMSC. To establish the association of this genetic variant in the CTLA-4 gene with the susceptibility of NMSC carcinogenesis in the Western Mexican population, samples from 150 BCC patients, 150 SCC patients, and 150 healthy individuals as the reference group (RG) were analyzed by endpoint PCR, followed by electrophoresis to genotype the samples. We found that the short-repeat 104/104 bp genotype may be a risk factor for BBC carcinogens (OR = 2.92, p = 0.03), whereas the long-repeat 106/106 bp genotype may be a protective factor for both BCC (OR = 0.13, p = 0.01) and SCC (OR = 0.32, p = 0.01) susceptibility. Our results show that in the Western Mexican population, long-repeat (AT)n variants in the CTLA-4 gene are associated with a protective factor in BCC and SCC. In contrast, short repeats are associated with a risk factor.

Uncovering the Expression Pattern of the Costimulatory Receptors ICOS, 4-1BB, and OX-40 in Exhausted Peripheral and Tumor-Infiltrating Natural Killer Cells from Patients with Cervical Cancer.

Cervical cancer (CC) poses a significant health burden, particularly in low- and middle-income countries. NK cells play a crucial role against CC; however, they can become exhausted and lose their cytotoxic capacity. This work explores the expression of costimulatory receptors (ICOS, 4-1BB, OX-40) in exhausted NK cells from CC patients. Peripheral blood and tumor biopsies were collected, and flow cytometry was used to evaluate the expression of costimulatory receptors in exhausted NK cells. There is an increase of peripheral exhausted NK cells (PD-1+TIGIT+) in CC patients; this subpopulation has a selectively increased expression of the costimulatory receptors ICOS and 4-1BB. An exhausted population is also highly increased in tumor-infiltrating NK cells, and it shows a dramatically increased expression of the costimulatory receptors ICOS (>15×) and 4-1BB (>10×) compared to peripheral NK cells. The exhausted cells, both in the periphery and in the tumor infiltrating lymphocytes (TILs), are also more likely than non-exhausted NK cell populations (PD-1-TIGIT-) to express these costimulatory receptors; increases ranging from 2.0× ICOS, 2.4× 4-1BB, and 2.6× OX-40 in CD56dim PBMCs to 1.5× ICOS, 5× 4-1BB, and 10× OX-40 in TILs were found. Our study demonstrates for the first time the increased expression of the costimulatory receptors ICOS, 4-1BB, and OX-40 in peripheral CD56dim, CD56bright, and tumor-infiltrating NK cells in CC. Targeting these receptors for stimulation could reverse exhaustion and be a promising immunotherapy strategy.

New Advances in the Study of CMTM6, a Focus on Its Novel Non-Canonical Cellular Locations, and Functions beyond Its Role as a PD-L1 Stabilizer.

CMTM6 is a membrane protein that acts as a regulator of PD-L1, maintaining its expression on the cell surface, and can prevent its lysosome-mediated degradation. It is unknown if CMTM6 is present in the plasma of patients with cervical cancer, and if it has non-canonical subcellular localizations in cell lines derived from cervical cancer. Our objective was to determine whether CMTM6 is found in plasma derived from cervical cancer patients and its subcellular localization in cell lines. Patient plasma was separated into exosome-enriched, exosome-free, and total plasma fractions. The levels of CMTM6 in each fraction were determined using ELISA and Western blot. Finally, for the cellular model, HeLa, SiHa, CaSki, and HaCaT were used; the subcellular locations of CMTM6 were determined using immunofluorescence and flow cytometry. Soluble CMTM6 was found to be elevated in plasma from patients with cervical cancer, with a nearly three-fold increase in patients (966.27 pg/mL in patients vs. 363.54 pg/mL in controls). CMTM6 was preferentially, but not exclusively, found in the exosome-enriched plasma fraction, and was positively correlated with exosomal PD-L1; CMTM6 was identified in the membrane, intracellular compartments, and culture supernatant of the cell lines. These results highlight that CMTM6, in its various presentations, may play an important role in the biology of tumor cells and in immune system evasion.

Haplotypes of [-794(CATT)5-8 /-173G>C] MIF gene polymorphisms and its soluble levels in cutaneous squamous cell carcinoma in western Mexican population.

BACKGROUND: Some cytokines are strongly implicated in the development of squamous cell carcinoma (SCC) such as the Macrophage migration inhibitory factor (MIF). The haplotype -794 (CATT)5-8 /-173G>C in MIF gene polymorphisms has been associated with some types of cancer. The aim of this study is to establish the possible association between the presence of this haplotype in the MIF gene and its subsequent soluble levels with the susceptibility of SCC in western Mexican population. METHODS: This study included 175 SCC patients and 175 age-sex-matched individuals as a reference group (RG) from western Mexico. Genomic DNA was extracted from peripheral blood leukocytes. Polymorphisms were genotyped by endpoint PCR and PCR-RFLP, and the determination of MIF serum levels was measured by ELISA. Clinical characteristics were evaluated by a group of dermatologists. RESULTS: Analysis of [-794(CATT)5-8 /-173G>C] MIF gene polymorphisms showed that the 5C (OR = 2.7, p = 0.02) and the 7G (OR = 3.39, p < 0.01) haplotypes are associated with susceptibility in SCC. MIF soluble levels in SCC patients showed a median of 13.93 ng/mL, whereas the reference group showed 6.000 ng/mL. CONCLUSIONS: Our findings suggest that 5C and 7G [-794(CATT)5-8 /-173G>C] MIF gene haplotypes are associated with susceptibility to SCC and that SCC patients present increased soluble levels of MIF.