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Phosphatase and tensin homolog on chromosome ten (PTEN) is one of the most frequently inactivated tumor suppressors in various tumor types. MicroRNA-21 (miR-21) may affect tumor progression by post-transcriptional repression of expression of tumor suppressors, such as PTEN. This study was conducted to evaluate the significance of PTEN expression in pulmonary neuroendocrine (NE) tumors and to analyze the relationship between PTEN and miR-21 expressions.
Expressions of PTEN and miR-21 were investigated by immunohistochemistry and real time reverse transcription-polymerase chain reaction, respectively, in 75 resected pulmonary NE tumors (23 typical carcinoids [TCs], nine atypical carcinoids [ACs], 22 large cell NE carcinomas [LCNECs], and 21 small cell lung carcinomas [SCLCs]).
Loss of PTEN expression was observed in four of 23 TCs (17.4%), four of nine ACs (44.4%), 16 of 22 LCNECs (72.7%) and nine of 21 SCLCs (42.9%) (p=.025). The expression level of miR-21 was significantly higher in high-grade NE carcinomas than in carcinoid tumors (p<.001). PTEN expression was inversely correlated with miR-21 expression (p<.001).
This study suggests that aberrant expression of PTEN in relation to miR-21 may represent an important step in the development and progression of pulmonary NE tumors.
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There is confusion in the diagnosis and biological behaviors of gastroenteropancreatic neuroendocrine tumors (GEP-NETs), because of independently proposed nomenclatures and classifications. A standardized form of pathology report is required for the proper management of patients.
We discussed the proper pathological evaluation of GEP-NET at the consensus conference of the subcommittee meeting for the Gastrointestinal Pathology Study Group of the Korean Society of Pathologists. We then verified the prognostic significance of pathological parameters from our previous nationwide collection of pathological data from 28 hospitals in Korea to determine the essential data set for a pathology report.
Histological classification, grading (mitosis and/or Ki-67 labeling index), T staging (extent, size), lymph node metastasis, and lymphovascular and perineural invasion were significant prognostic factors and essential for the pathology report of GEP-NET, while immunostaining such as synaptophysin and chromogranin may be optional. Furthermore, the staging system, either that of the 2010 American Joint Cancer Committee (AJCC) or the European Neuroendocrine Tumor Society (ENETS), should be specified, especially for pancreatic neuroendocrine neoplasms.
A standardized pathology report is crucial for the proper management and prediction of prognosis of patients with GEP-NET.
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There is a subjective disagreement about nuclear chromatin in the field of pathology. Objective values of red, green, and blue (RGB) light intensities for nuclear chromatin can be obtained through a quantitative analysis using digital images.
We examined 10 cases of well differentiated neuroendocrine tumors of the rectum, small cell lung carcinomas, and moderately differentiated squamous cell lung carcinomas respectively. For each case, we selected 30 representative cells and captured typical microscopic findings. Using an image analyzer, we determined the longest nuclear line profiles and obtained graph files and Excel data on RGB light intensities. We assessed the meaningful differences in graph files and Excel data among the three different tumors.
The nucleus of hematoxylin and eosin-stained tumor cells was expressed as a combination of RGB light sources. The highest intensity was from blue, whereas the lowest intensity was from green. According to the graph files, green showed the most noticeable change in the light intensity, which is consistent with the difference in standard deviations.
The change in the light intensity for green has an important implication for differentiating between tumors. Specific features of the nucleus can be expressed in specific values of RGB light intensities.
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