As the perioperative chemotherapy has been widely implemented on the management of gastric cancer patients, heterogeneity of clinical outcomes has been evidenced in parallel to different histopathological regression pattern of gastric cancer cells. Tumor histological response to preoperative therapy has been graded by various systems in order to categorize the amount of regressive changes induced by chemotherapy in relation to residual tumor. In this context, tumor regression grading (TRG) systems might provide important prognostic information as the variety of tumor response may imply on different clinical outcomes with impact in survival rates. Moreover, gastric cancer behavior varies enormously upon individual factors such as histological classification and tumor anatomic site of involvement that have been shown to affect the TRG interpretation. On the other hand, some studies have assessed the role of molecular markers as a predictor of tumor response to neoadjuvant chemotherapy in terms of TRG. Thus, the aim of this review is to evaluate how TRG has been interpreted in gastric cancer, discuss their clinical and prognostic relevance and also address the molecular markers involved in this process.
EZH2 is an important epigenetic regulator, but its role in diffuse large B‐cell lymphoma (DLBCL) pathogenesis and its relationship with MYC, BCL2, and TP53 expression, chromosomal rearrangements, and clinical features are still poorly understood. So, we investigated EZH2 expression and its associations with the immunophenotypic presentations, including MYC, BCL2, and TP53 expression, MYC, BCL2, and BCL6 translocation status, clinicopathological features, and therapeutic response to R‐CHOP in a series of 139 DLBCL cases. EZH2 positivity was associated with MYC and TP53 expression (p = 0.0002 and p = 0.0000, respectively) and to high proliferative index (Ki67>70%, p = 0.0082). No associations were found among EZH2 expression and chromosomal translocation status. The non‐germinal center (nGC) DLBCL presented most of associations observed in the general sample; however, only TP53 immunodetection showed associations with EZH2 expression in the germinal center (GC) DLBCL. EZH2 expression had no impact on therapeutic efficacy in R‐CHOP‐treated patients. In conclusion, EZH2 seems to be upregulated by MYC, to rely on TP53 alterations, and is associated with high proliferative tumors in DLBCL, which might be dependent on GC or nGC subclassifications. Furthermore, it is not a therapeutic efficacy marker to R‐CHOP in our series.
TP53 mutations and polymorphisms have been widely related to many cancers as long as these alterations may impair its capacity to induce cell cycle arrest, DNA repair mechanisms, and apoptosis. Although TP53 alterations have been studied in astrocytic tumors, there is a lack of analysis considering specific TP53 mutations and their associations with p53 immunostainning, polymorphisms and their significance among the histological grades. Thus, we analyzed TP53 alterations in exons 2-11, including the codon 72 polymorphism, using DNA sequencing in 96 astrocytic gliomas (18 grade I, 20 grade II, 14 grade III, and 44 grade IV). Also, immunohistochemistry was assessed to evaluate the p53 protein expression. In this study, we found that the higher histological grades were statistically associated with TP53 mutations. Some of these mutations, such as TP53 P98T and TP53 G244S, seemed to be a specific marker for the higher grades, and the TP53 E286K mutation appears to be a World Health Organization grade III-IV progression marker. Also, the TP53 P98T mutation, in exon 4, is very likely to be important on the stabilization of the p53 protein, leading to its immunopositivity and it is potentially associated with the TP53 72Pro/Pro genotype.
Mammary hibernomas are extremely rare benign tumors composed of brown fat cells, with only five cases previously reported in the literature. We report the case of a 42-year-old female patient with a painless growing mass in her right breast. A partial mastectomy was performed, and the diagnosis of hibernoma was confirmed by the histological features and the immunohistochemical profile. Although hibernoma is a benign tumor, its main differential diagnoses include aggressive lesions, making the accurate diagnosis essential to provide adequate care to the patient.
MTHFR C677T and Helicobacter pylori infection are believed to play critical roles in the DNA methylation process, an epigenetic feature frequently found in gastric cancer. The aim of this study was to verify the associations between the MTHFR C677T polymorphism and the methylation status of three gastric cancer-related genes. The influence of H. pylori strains was also assessed. DNA extracted from 71 gastric tumor samples was available for MTHFR C677T genotyping by PCR-RFLP, promoter methylation identification by MS-PCR and H. pylori detection and posterior subtyping (cagA and vacA genes) by PCR. In the distal tumors, a positive correlation was found between the methylation of CDKN2A and the allele T carriers (r=0.357; p=0.009). Considering the eldest patients (age ≥60 years old), this correlation was even higher (r=0,417; p=0.014). H. pylori infection by highly pathogenic strains (cagA+/vacAs1m1) was also found correlated to promoter methylation of CDKN2A and the allele T carriers in distal tumors (r=0.484; p=0.026). No significant correlation was verified between MTHFR C677T genotype and promoter methylation status when we analyzed the general sample. DNA methylation in CDKN2A associated to the MTHFR 677T carrier is suggested to be a distal tumor characteristic, especially in those 60 years old or older, and it seems to depend on the infection by H. pylori cagA/vacAs1m1 strains.
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