Yolanda Zamorano-Orozco

p53 expresado en la mucosa gástrica de pacientes infectados por Helicobacter pylori

BACKGROUND Helicobacter pylori (Hp) is recognized as a type 1 carcinogen for gastric cancer associated with pre-neoplastic lesions (atrophy and intestinal metaplasia [IM]). Its relation with p53, which intervenes in the cell cycle, has had contradictory results. AIMS To analyze p53 expression in gastric mucosa and its relation with Hp infection. METHODS A 3-month prospective, observational, cross-sectional study was conducted. Patients that had no evidence of acute or clinically significant gastric pathology had biopsies taken according to the Sydney system at the Hospital Juárez de México and the histopathologic studies were done at the Hospital Español de México. RESULTS Hp prevalence was 32.7% in 104 patients. There were no cases of atrophy or dysplasia. A total of 91% of the infected patients were positive for p53. Of the non-infected patients, 14% were positive for p53 and 60% of them had IM. Of the IM patients, 75% presented with positive p53. Of the patients without IM, 31 presented with positive p53, and Hp was positive in 85% of them. There was association between Hp and p53 and between p53 and IM (P<.0001 and P<.0006, respectively). CONCLUSIONS Significant association was shown between Hp and p53 expression, even in patients with pre-neoplastic lesions that no longer presented with Hp. Given that the identification of pre-neoplastic lesions is important for the prevention of cancer, immunohistochemistry could benefit routine biopsy carried out during endoscopy for the detection of Hp, by identifying patients with expression of the important oncogene regulator, p53.

Elastografía cuantitativa por ultrasonido endoscópico en la estadificación ganglionar del cáncer de esófago

Endoscopic ultrasound (EUS)-guided fine-needle aspiration biopsy (FNAB) is the gold standard for determining lymph node involvement with diagnostic accuracy > 95%, even though it cannot be carried out passing the needle through the primary tumor or vascular structures, and it can be technically difficult. Four conventional criteria characteristic of malignant lymph nodes (LN) utilizing EUS in mode B are: > 1 cm, rounded, hypoechoic, and sharp margins; however, the sensitivity (Sn) and specificity (Sp) of these criteria in distinguishing malignancy exceed 80% only when all of them are present. Elastography (EG) is applied in real time during EUS (EUS-EG) and it evaluates tissue elasticity and hardness. Clinical research has shown favorable results in the differentiation between benign and malignant tissues. EG utilizes a color map (red-green-blue) in the region of interest (ROI) and can be qualitative and quantitative. The blue areas indicate hard tissue, green and yellow indicate intermediate hardness, and red indicates soft tissue. Qualitative EUS-EG is determined through color patterns and has demonstrated an overall accuracy of 88.1% in detecting LN malignancy. Quantitative EUS-EG utilizes second-generation software, is more objective, and enables stiffness quantification by comparing 2 different tissue zones (A and B) of the ROI. Area A includes the greatest surface area of the tissue being studied and area B is a reference surface of normal adjacent tissue that is in red. The A/B coefficient determines the strain ratio (SR). The reported diagnostic accuracy for determining LN malignancy is 90%.