Histological tumor necrosis (TN) has been reported to indicate a poor prognosis for different human cancers. It is generally accepted that TN results from chronic ischemic injury due to rapid tumor growth. However, whether insufficient tumor vascularization and inadequate tumor cell oxygenation are the only factors causing TN remains controversial. Mitotic catastrophe is considered to occur as a result of dysregulated/failed mitosis, leading to cell death. We hypothesize that mitotic catastrophe, induced by hypoxic stress, may lead to the TN which is observed in high grade carcinomas. The current review describes the morphological features of TN in malignant epithelial tumors. In addition, evidence regarding the involvement of mitotic catastrophe in the induction of TN in human carcinomas is discussed.
ORIGINAL RESEARCH ARTICLEand low survival, lung cancer is the most common cause of death from cancer worldwide with 1.59 million deaths, more than 1 million in men and 491,000 in women (1). In Europe, it is the third most common cause of cancer, after breast and prostate cancer (1).The epidemiology of lung cancer is changing in many areas of the world in terms of incidence by gender, age class and histological type (3, 4). Different histological subtypes are linked to different risk factors; for example, outdoor particulate matter has been recognized as a stronger risk factor for adenocarcinoma of the lung than for other histologies, while smoking has been associated in the past mainly with squamous cell carcinoma. However, because of the dissemination of low-tar filter cigarettes, smoking has been hypothesized to be linked also with adenocarcinoma (3). Lung cancer appears to have biologically different characteristics in men and women. The histological distribution of lung cancer subtypes is distinctly different and female smokers are more likely to develop adenocarcinoma of the lung than squamous cell carcinoma, which is more common in men (4). However, the differences in incidence rates between men and women are mainly attributable to the different exposure to tobacco smoking (3).
Autophagy represents a catabolic process in which cellular protein and organelles are engulfed into autophagosomes, digested in lysosomes and reutilized for the cellular metabolism. In neoplastic conditions, autophagy may act either as a tumour suppressor avoiding the accumulation of damaged proteins and organelles or as a mechanism of cell survival promoting the tumour growth. Although enhanced autophagy has been reported in hypoxic areas of solid tumors, there are only few ultrastructural reports concerning the relationships between autophagy and tumor grade. In the present study, we have performed an ultrastructural investigation aimed to document autophagy in a cohort of advanced gastric carcinomas of tubular type, correlating the observed findings with low and high tumor grade. Among 71 surgically resected cases of advanced gastric carcinomas, we have selected twelve low-grade and thirteen high-grade tubular adenocarcinomas. Autophagic vacuoles (AV) were only occasionally found in low-grade tubular carcinomas, while they constituted a frequent finding in high-grade ones (p < 0.01). Moreover, in high-grade tubular adenocarcinomas, our data revealed a morphologic association between autophagy and nuclear changes, such as multinucleation, micronucleation and nuclear buds, largely considered as ultrastructural aspects of mitotic instability. However, an increased autophagy was associated with organelle-poor cytoplasm or a senescent phenotype, characterized by lipofuscin granules and cytoplasmic vacuoles. In the light of our observations, it may be suggested that autophagy should be considered a phenomenon mainly related to the cellular differentiation and tumor progression.
Pleomorphic carcinoma is an aggressive neoplasm defined by the World Health Organization (WHO) as a poorly differentiated (squamous cell carcinoma or adenocarcinoma) or undifferentiated carcinoma in which at least 10% spindle and/or giant cells are identified, or as a carcinoma constituted purely of spindle and giant cells. Although this entity has initially been shown in the lung, it has been described also in extrapulmonary locations, with only one report for a colonic site. A 65-year-old woman developed a caecal tumour. Gross examination revealed an endophytic/ulcerative mass 7 cm in length. Microscopically, the tumour was a poorly differentiated adenocarcinoma with a pleomorphic component that occupied more than 10% of the specimen. The tumour shared these histopathological findings with pulmonary giant cell carcinoma but differed in other clinicopathological features such as a pushing growth pattern, stage pT3N1, and an uneventful outcome 24 months after operation. The pleomorphic component showed morphological and immunohistochemical features compatible with mitotic catastrophe, a non-apoptotic cell death occurring in cycling cells after aberrant mitosis. These features included multinucleation, micronucleation, atypical mitoses, foci of geographic necrosis, as well as immunohistochemical overexpression of p53 and Ki-67. The interpretation of the pleomorphic component as morphological expression of mitotic catastrophe may be useful in comprehending the pathogenesis of this rare neoplasm, and it may have practical implications as a potential cancer therapeutic target.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with đź’™ for researchers
Part of the Research Solutions Family.