Martha Lucía Serrano

Altered HLA Class I and HLA-G Expression Is Associated with IL-10 Expression in Patients with Cervical Cancer

Although high-risk human papillomaviruses (HPVs) are an important risk factor in the etiopathogenesis of cervical cancer, increasing evidence suggests that the ability to avoid immune surveillance seems to be linked to the transforming potential of HPV and a rapid progression to cancer. In other cancer models, IL-10 contributes to impair anti-tumor immune response either by downregulating human leukocyte antigen Class I (HLA-I) expression or by increasing HLA-G expression. To comprehend how these alterations could contribute to evasion of immune surveillance in cervical cancer, we analyzed HLA-I, HLA-G and IL-10 expressions by immunohistochemistry in 63 biopsies from patients with cervical intraepithelial neoplasia III (CIN-III) and cervical cancer. Immunohistochemistry showed absent or weak HLA-I expression in 50/59 cases. In these cases, a high percentage had loss of heterozygosis. IL-10 and HLA-G expression were observed in 46.6 and 27.6% of cases, respectively. Concurrent upregulation of IL-10 was found in 87.5% of HLA-G positive cases (p = 0.000). Similarly, a significant association between IL-10 expression and HLA-I downregulation was found (p = 0.028). Finally, we observed higher HLA-G expression in patients with HLA-I downregulation than in those with normal HLA-I expression (p = 0.004). Our results suggest that, in cervical cancer, the IL-10 expression may induce an immunosuppressive environment by upregulating HLA-G expression and downregulating HLA class I expression.

Mutaciones Ha-RAS en fibroblastos del estroma cervical de neoplasias escamosas de cuello uterino

El estroma es un importante elemento para el tejido epitelial, capa sub-epitelial compuesta de matriz extracelular y de varios tipos de celulas. El estroma es mantenido, remodelado y reparado por fibroblastos residentes, apoya e instruye al epitelio, y es esencial para la funcion epitelial. Actualmente se reconoce que los cambios del estroma son necesarios para el establecimiento de cancer ya que anteriormente se consideraba como un espectador frente a la expansion clonal y a la adquisicion de caracteristicas malignas de las celulas tumorales. La mayoria de estudios sobre el estroma y su relacion con la generacion, progresion y metastasis de neoplasias se han centrado especialmente en canceres como el de mama, prostata, gastrico, colorectal y cancer cervical. Los reportes sobre cancer cervical abordan especificamente aspectos como rasgos genomicos y clonalidad en carcinogenesis cervical. Sin embargo, la presencia de mutaciones en oncogenes Ha-ras en celulas estromales y su contribucion a la generacion y progresion de neoplasias escamosas cervicales aun no ha sido reportada. El proposito de este estudio fue detectar la presencia de mutaciones Ha-RAS en fibroblastos del estroma de biopsias de la zona de transformacion del cuello uterino. Se seleccionaron ocho muestras de tejido fresco congelado de pacientes diagnosticadas con neoplasia intraepitelial cervical de tipo escamoso (NIC I, NIC II, NIC III), cancer in situ y carcinoma escamocelular infiltrante, tejido en el cual solo se encontraba representado el estroma sin evidencia de componente epitelial tumoral residual, y para cada uno de los cuales se contaba con el tejido cervical de control incluido en parafina que confirmaba la presencia de proceso neoplasico escamoso cervical. La deteccion de mutaciones Ha-ras codon 12 fue realizada mediante un PCR-SSCP no radioactivo y analisis enzimatico de restriccion. La mutacion hallada para un cambio de una glicina por una valina en el codon 12 del oncogen Haras fue detectada en una sola muestra (12.5%), NIC III. La presencia de una mutacion puntual del oncogen Ha-ras en el estroma de uno de estos casos analizados, representa un cambio importante, y sugiere una via alterna que podria involucrar inestabilidad genetica estromal en la generacion de neoplasias intraepiteliales y progresion del cancer de cuello uterino.

Abstract B61: Ha‐RAS mutations in fibroblast of the cervical stroma of squamous neoplasias of the uterine cervix

The stroma is maintained, renovated, and repaired by resident fibroblasts, supports and instructs the epithelium, and is essential for epithelial function. Now recognized that stromal changes are necessary for the establishment of cancer and previously considered as a spectator in front of the clonal expansion and acquisition of malignant characteristics of tumor cells. Most studies on the stroma and t its relationship with the generation, progression and metastasis of cancer in which involve multiple steps of tumorigenesis and the microenvironment, have focused especially on cancers such as breast and others as cancer of prostate, gastric, colorectal and cervical cancer. Reports of cervical cancer specifically address issues such as clonality and genomic features in cervical carcinogenesis. However, the presence of mutations Ha‐RAS oncogen in stromal cells and their contribution to the generation and progression of cervical squamous neoplasia has not yet been reported. The aim of this study was detect and determine the frequency of mutations Ha‐RAS in stromal fibroblasts from biopsies of the transformation zone of the uterine cervix. We selected eight samples of fresh frozen tissue of patients diagnosed with cervical intraepithelial neoplasia squamous (CIN I, CIN II, CIN III), cancer in situ and invasive squamous cell carcinoma, tissue in which it was represented only the stroma, without evidence of residual tumoral epithelial component, and each of whom had cervical tissue in paraffin‐embedded control confirming the presence of cervical squamous neoplasia. The detection of Ha‐ras mutations in codon 12 was performed using a nonradioactive PCR‐SSCP and restriction enzyme analysis. The mutation found for a substitution of a glycine by a valine at codon 12 of Ha‐RAS was detected in alone sample (12.5%), CIN III. The non‐detection of the GTC mutation in the remaining seven samples could be due to somatic mutation that this represented only a small fraction (approximately 15%) of total DNA analyzed (33), as well as a topographical heterogeneity likely distribution of these mutations. The presence of a point mutation of Ha‐RAS oncogene in the stroma of one case studied, represents an important change, this mutation prevents the conversion of active to inactive form, and suggest an alternative pathway involving stromal genetic instability in the generation of intraepithelial neoplasia and progression of the cervical cancer. Citation Information: Cancer Prev Res 2010;3(1 Suppl):B61.