Journal of Pathology and Translational Medicine

Original Articles

Correlation between HER2 gene copy number and immunohistochemistry categories in HER2-negative breast cancer: diagnostic utility for differentiating HER2-null, ultralow, and low tumors: Min Chong Kim, Young Kyung Bae; Received September 1, 2025 Accepted November 7, 2025 Published online February 25, 2026; DOI: https://doi.org/10.4132/jptm.2025.11.07 [Epub ahead of print]

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Abstract PDF: Background
The recent recognition of human epidermal growth factor receptor 2 (HER2)–low and HER2-ultralow breast cancers (BCs) has expanded the therapeutic relevance of HER2 testing in the antibody-drug conjugate era. However, the biological continuum of HER2 expression measured by immunohistochemistry (IHC) and its relationship with the HER2 gene copy number remain unclear. Methods: We retrospectively analyzed 135 HER2-negative invasive BCs and reclassified them as HER2-null (IHC 0), HER2-ultralow (0+), or HER2-low (1+ or 2+ without amplification). HER2 gene copy number was determined using silver-enhanced in situ hybridization. Statistical analyses were performed to compare HER2 copy number among IHC categories and evaluate the discriminatory value of HER2 copy number for distinguishing IHC subgroups. Results: The mean HER2 copy number increased stepwise across IHC categories: 1.95 ± 0.54 (null), 2.03 ± 0.43 (ultralow), 2.25 ± 0.65 (low, 1+), and 3.29 ± 1.05 (low, 2+). Significant differences were observed between the ultralow and low groups (p = .003) and between the null and low groups (p < .001), but not between the null and ultralow groups or between the ultralow and 1+ groups. Conclusions: HER2 gene copy number was positively correlated with protein expression as reflected by IHC categories. Although HER2 gene copy number was statistically higher in HER2-low than in HER2-null tumors, the substantial overlap in copy number ranges likely limits its utility in distinguishing HER2-low from HER2- null BCs.

Revisiting human sparganosis: a pathologic review from a single institution: Jeemin Yim, Young A Kim, Jeong Hwan Park, Hye Eun Park, Hyun Beom Song, Ji Eun Kim; J Pathol Transl Med. 2026;60(1):83-91. Published online January 9, 2026; DOI: https://doi.org/10.4132/jptm.2025.10.14

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Sparganosis is a rare parasitic infection caused by Spirometra species. Although it was relatively common in the past, it is now often overlooked. In this study, we review cases diagnosed through histopathological examination at a single institution in recent years to raise awareness of this neglected parasitic disease. Methods: We retrospectively analyzed cases of human sparganosis identified in the pathology archives of a single institution in South Korea between 2004 and 2025. A comprehensive review was conducted, including demographic data, clinical features, lesion locations, imaging findings, exposure history (such as dietary habits), and histopathologic findings. Results: A total of 15 patients were identified, including 10 females and 5 males, with a mean age of 65.1 years. Lesions were most commonly located in the lower extremities and breast. Imaging findings were largely nonspecific, with ultrasonography being the most frequently used modality. In most cases, clinical suspicion of sparganosis was absent, and excision was performed under the impression of a benign or malignant tumor. Histologically, variably degenerated parasitic structures were identified within granulomatous inflammation. However, preserved features such as calcospherules and tegumental structures facilitated definitive diagnosis. Conclusions: This study underscores the importance of recognizing the characteristic histopathological features of sparganosis, which can allow for accurate diagnosis even in the absence of clinical suspicion. Although rare, sparganosis remains a relevant diagnostic consideration in endemic regions, particularly in East Asia.

Spectrum of thyroiditis types: clinical, cytomorphological, and radiological findings: Anam Singh, Indrajeet Kundu; J Pathol Transl Med. 2025;59(6):421-433. Published online November 6, 2025; DOI: https://doi.org/10.4132/jptm.2025.08.13

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Abstract PDF: Background
Thyroiditis encompasses a range of inflammatory conditions affecting the thyroid gland. Lymphocytic thyroiditis (LT) is a common form of thyroiditis, with acute suppuration of the thyroid, while tuberculous thyroiditis is relatively rare. Fine-needle aspiration cytology (FNAC) remains a safe and cost-effective tool for diagnosing thyroid-related diseases, especially when paired with ultrasound (US) and clinical examination. Methods: This is a cross-sectional study including 21 cases. The cases were reported as thyroiditis on US and FNAC, and the findings were correlated with patient clinical history, symptoms during presentation, and serological profiles. Results: The cases of thyroiditis encompassed the more common forms, LT and subacute granulomatous thyroiditis (SAT), as well as relatively rare forms like tuberculous thyroiditis and thyroid abscess. Cases of follicular neoplasms (FN) arising in the context of LT also are included in this study. The case of tuberculous thyroiditis presented as a bulky thyroid gland that appeared heterogeneous on US with extensive necrosis on FNAC. The cases of thyroid abscess and SAT presented with painful neck swellings, with granulomas in the latter cases. US features of LT showed an array of appearances ranging from pseudonodular to an atrophic thyroid gland. All cases of FN showed a lymphocytic background. Conclusions: Thyroiditis is a commonly encountered condition that needs to be sub-categorized accurately into acute, subacute, and chronic types for appropriate clinical management, as they can sometimes show overlapping features. Though rare, acute suppurative and tuberculous thyroiditis are often encountered and warrant immediate care and treatment.

BRCA-mutated gastric adenocarcinomas are associated with chromosomal instability and responsiveness to platinum-based chemotherapy: Ji Hyun Oh, Chang Ohk Sung, Hyung-Don Kim, Sung-Min Chun, Jihun Kim; J Pathol Transl Med. 2023;57(6):323-331. Published online November 14, 2023; DOI: https://doi.org/10.4132/jptm.2023.10.22

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Abstract PDF Supplementary Material

Background
Homologous recombination defect is an important biomarker of chemotherapy in certain tumor types, and the presence of pathogenic or likely pathogenic mutations involving BRCA1 or BRCA2 (p-BRCA) mutations is the most well-established marker for the homologous recombination defect. Gastric cancer, one of the most prevalent tumor types in Asia, also harbors p-BRCA mutations.
Methods
To investigate the clinical significance of p-BRCA mutations, we analyzed 366 gastric cancer cases through next-generation sequencing. We determined the zygosity of p-BRCA mutations based on the calculated tumor purity through variant allelic fraction patterns and investigated whether the presence of p-BRCA mutations is associated with platinum-based chemotherapy and a certain molecular subtype.
Results
Biallelic p-BRCA mutation was associated with better response to platinum-based chemotherapy than heterozygous p-BRCA mutation or wild type BRCA genes. The biallelic p-BRCA mutations was observed only in the chromosomal instability subtype, while all p-BRCA mutations were heterozygous in microsatellite instability subtype.
Conclusions
In conclusion, patients with gastric cancer harboring biallelic p-BRCA mutations were associated with a good initial response to platinum-based chemotherapy and those tumors were exclusively chromosomal instability subtype. Further investigation for potential association with homologous recombination defect is warranted.

Citations

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Reviews

Infections and immunity: associations with obesity and related metabolic disorders: Amitabha Ray, Melissa J. L. Bonorden, Rajashree Pandit, Katai J. Nkhata, Anupam Bishayee; J Pathol Transl Med. 2023;57(1):28-42. Published online January 15, 2023; DOI: https://doi.org/10.4132/jptm.2022.11.14

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18 Web of Science
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