Different Threshold of Malignancy for <i>RAS</i>-like Thyroid Tumors Causes Significant Differences in Thyroid Nodule Practice
Histopathological diagnosis of papillary thyroid carcinomas (PTCs) is prone to significant observer variation due to different thresholds of <i>RAS</i>-like nuclear changes among pathologists. This gap recently widened due to a defensive attitude by Western pathologists where malpractice...
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MDPI AG
2022-02-01
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| Series: | Cancers |
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| Online Access: | https://www.mdpi.com/2072-6694/14/3/812 |
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| author | Kennichi Kakudo |
| author_facet | Kennichi Kakudo |
| author_sort | Kennichi Kakudo |
| collection | DOAJ |
| description | Histopathological diagnosis of papillary thyroid carcinomas (PTCs) is prone to significant observer variation due to different thresholds of <i>RAS</i>-like nuclear changes among pathologists. This gap recently widened due to a defensive attitude by Western pathologists where malpractice litigation is significant. Cases with delicate <i>RAS</i>-like nuclear changes are follicular adenomas when they are noninvasive, follicular carcinomas when invasive, and follicular variant PTCs when they have fully developed PTC-type nuclear features in Asian practice. The different diagnostic threshold of PTC nuclear features resulted in a high (50–90%) incidence of <i>BRAFV600E</i> mutation of PTCs in most Asian countries, whereas it was low (35–50%) in most Western patient cohorts. The contamination of indolent <i>RAS</i>-like tumors in the malignant PTC category in Western patient cohorts explains why the <i>BRAFV600E</i> gene test identifies aggressive PTCs. However, the <i>BRAFV600E</i> test has no prognostic value for Asian PTC patients because most biologically benign or low-risk <i>RAS</i>-like tumors are excluded from PTC. All prognostic analyses of thyroid carcinomas before 2017 must be re-evaluated because most clinical guidelines were established based on data obtained from Western patient cohorts where a significant number of indolent <i>RAS</i>-like tumors were misclassified in the malignant category. |
| first_indexed | 2024-03-10T00:04:55Z |
| format | Article |
| id | doaj.art-0cb974c5d3284c89aa0f49688b258a2f |
| institution | Directory Open Access Journal |
| issn | 2072-6694 |
| language | English |
| last_indexed | 2024-03-10T00:04:55Z |
| publishDate | 2022-02-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Cancers |
| spelling | doaj.art-0cb974c5d3284c89aa0f49688b258a2f2023-11-23T16:09:06ZengMDPI AGCancers2072-66942022-02-0114381210.3390/cancers14030812Different Threshold of Malignancy for <i>RAS</i>-like Thyroid Tumors Causes Significant Differences in Thyroid Nodule PracticeKennichi Kakudo0Department of Pathology, Cancer Genome Center and Thyroid Disease Center, Izumi City General Hospital, Izumi 594-0073, JapanHistopathological diagnosis of papillary thyroid carcinomas (PTCs) is prone to significant observer variation due to different thresholds of <i>RAS</i>-like nuclear changes among pathologists. This gap recently widened due to a defensive attitude by Western pathologists where malpractice litigation is significant. Cases with delicate <i>RAS</i>-like nuclear changes are follicular adenomas when they are noninvasive, follicular carcinomas when invasive, and follicular variant PTCs when they have fully developed PTC-type nuclear features in Asian practice. The different diagnostic threshold of PTC nuclear features resulted in a high (50–90%) incidence of <i>BRAFV600E</i> mutation of PTCs in most Asian countries, whereas it was low (35–50%) in most Western patient cohorts. The contamination of indolent <i>RAS</i>-like tumors in the malignant PTC category in Western patient cohorts explains why the <i>BRAFV600E</i> gene test identifies aggressive PTCs. However, the <i>BRAFV600E</i> test has no prognostic value for Asian PTC patients because most biologically benign or low-risk <i>RAS</i>-like tumors are excluded from PTC. All prognostic analyses of thyroid carcinomas before 2017 must be re-evaluated because most clinical guidelines were established based on data obtained from Western patient cohorts where a significant number of indolent <i>RAS</i>-like tumors were misclassified in the malignant category.https://www.mdpi.com/2072-6694/14/3/812papillary thyroid carcinoma<i>BRAFV600E</i><i>RAS</i>follicular adenomanoninvasive follicular thyroid neoplasm with papillary-like nuclear featureborderline tumor |
| spellingShingle | Kennichi Kakudo Different Threshold of Malignancy for <i>RAS</i>-like Thyroid Tumors Causes Significant Differences in Thyroid Nodule Practice Cancers papillary thyroid carcinoma <i>BRAFV600E</i> <i>RAS</i> follicular adenoma noninvasive follicular thyroid neoplasm with papillary-like nuclear feature borderline tumor |
| title | Different Threshold of Malignancy for <i>RAS</i>-like Thyroid Tumors Causes Significant Differences in Thyroid Nodule Practice |
| title_full | Different Threshold of Malignancy for <i>RAS</i>-like Thyroid Tumors Causes Significant Differences in Thyroid Nodule Practice |
| title_fullStr | Different Threshold of Malignancy for <i>RAS</i>-like Thyroid Tumors Causes Significant Differences in Thyroid Nodule Practice |
| title_full_unstemmed | Different Threshold of Malignancy for <i>RAS</i>-like Thyroid Tumors Causes Significant Differences in Thyroid Nodule Practice |
| title_short | Different Threshold of Malignancy for <i>RAS</i>-like Thyroid Tumors Causes Significant Differences in Thyroid Nodule Practice |
| title_sort | different threshold of malignancy for i ras i like thyroid tumors causes significant differences in thyroid nodule practice |
| topic | papillary thyroid carcinoma <i>BRAFV600E</i> <i>RAS</i> follicular adenoma noninvasive follicular thyroid neoplasm with papillary-like nuclear feature borderline tumor |
| url | https://www.mdpi.com/2072-6694/14/3/812 |
| work_keys_str_mv | AT kennichikakudo differentthresholdofmalignancyforirasilikethyroidtumorscausessignificantdifferencesinthyroidnodulepractice |