Mehtat Unlu

Background/Aims: Accurately determining the human epidermal growth factor receptor 2 (HER2) status is crucial in identifying suitable candidates for targeted therapy in gastric cancer, considering the cost and potential side effects of anti-HER2 treatments. This study aimed to assess HER2 overexpression/amplification prevalence in gastric and gastroesophageal cancer patients, its correlation with clinicopathological characteristics, and the consistency of HER2 status between biopsy and radical specimens. Materials and Methods: We analyzed data from 667 specimens of 600 gastric/gastroesophageal cancer patients at Dokuz Eylül University Faculty of Medicine from 2012 to 2021. The correlation of HER2 expression and amplification status and clinicopathological parameters were assessed. Furthermore, we compared HER2 status concordance between paired biopsy-radical specimens when both endoscopic and radical materials were present. Additionally, we compared HER2 status before and after treatment in patients receiving neoadjuvant chemotherapy. Results: In our study, +3 HER2 immunohistochemistry results were more common in gastroesophageal junction tumors (23%). Human epidermal growth factor receptor 2 immunohistochemistry positivity and HER2 gene amplification were found to be significantly more common in males, people over 65 years of age, and intestinal morphology. Overall concordance of HER2 status between radical and biopsy materials was 95.5%. Conclusion: The high HER2 concordance between the paired biopsy and radical samples holds significant importance in clinical management. This finding is particularly noteworthy since the HER2 assessment can generally be conducted on small/limited biopsy materi als in routine practice. Our study is the most extensive series from Türkiye and the Balkans, which will shed light on our country’s data by investigating the relationship of HER2 with clinicopathological parameters in gastric/gastroesophageal carcinomas. Cite this article as: Yuzuguldu RI, Sagol O, Unlu M, et al. HER2 status in gastric and gastroesophageal carcinomas: evaluation of histopathological findings, paired resection biopsy specimens, and the effect of neoadjuvant therapy: A single center study. Turk J Gastroenterol. 2025;36(6):357-370.

PURPOSE This paper aims to investigate the diagnostic performance of magnetic resonance imaging (MRI) in predicting the pathologic stage of locally advanced rectal cancer (LARC) after neoadjuvant chemo-radiotherapy (CRT) and the role of MRI in selecting patients with a pathologic complete response (ypCR). METHODS Restaging MRI (yMRI) examinations of 136 patients with LARC treated with neoadjuvant CRT fol-lowed by surgery were retrospectively analyzed by two radiologists. All examinations were per -formed on a 1.5 Tesla MRI machine with a pelvic phased-array coil. T2-weighted turbo spin-echo images and diffusion-weighted imaging were obtained. Histopathologic reports of the surgical specimens were the reference standard. The accuracy, sensitivity, specificity, positive and negative predictive values (PPV and NPV) of yMRI in predicting the pathologic T-stage (ypT), N-stage, and ypCR were calculated. The inter-observer agreement was evaluated using kappa statistics. RESULTS The yMRI results showed 67% accuracy, 59% sensitivity, 80% specificity, 81% PPV, and 56% NPV in identifying ypT (ypT0-2 versus ypT3-4). In predicting the nodal status, the yMRI results revealed 63% accuracy, 60% sensitivity, 65% specificity, 47% PPV, and 75% NPV. In predicting ypCR, the yMRI results showed 84% accuracy, 20% sensitivity, 92% specificity, 23% PPV, and 90% NPV. The kappa statistics revealed substantial agreement between the two radiologists. CONCLUSION Utilization of yMRI showed high specificity and PPV in predicting the tumor stage and high NPV in predicting the nodal stage; in addition, yMRI revealed moderate accuracy in the T and N classifica-tions, mainly due to underestimating the tumor stage and overestimating the nodal status. Finally, yMRI revealed high specificity and NPV but low sensitivity in predicting the complete response.

Objective: Granulomatous interstitial nephritis is a rare finding, and etiology differs by geography. We aimed to investigate the distribution of causes of granuloma/granulomata in the kidney and renal survival of these patients in a tertiary care hospital in Western Turkey.

Background/Aims: The importance of hyperplastic polyps during colorectal carcinogenesis is appreciated related to the understanding of serrated pathway. The morphologic subtypes of hyperplastic polyps in carcinogenesis and the nomenculature of lesions with both hyperplastic and adenomatous areas are controversial. We aimed to reveal the molecular properties of hyperplastic polyp subtypes and the molecular changes in polyps containing both hyperplastic and adenomatous areas. Matherial and Methods: 49 hyperplastic polyps [19 microvesicular (MVHP), 19 goblet-rich (GRHP), 11 mucin-poor (MPHP)] and 10 mixed hyperplastic and adenomatous polyps were analysed for KRAS, BRAF mutations and MSI with real-time PCR. Results: 68,4% of MVHPs and 81% of MPHPs which were localized in right colon had BRAF mutations. While none of the GRHPs showing a KRAS mutation with a rate of 73% was localized in the ascending colon, 63% of them were localized in the rectosigmoid area. In five (50%) of the mixed polyps, KRAS mutation was detected both in the hyperplastic and adenoma components. There was no BRAF mutation in any of the mixed polyps. However, in two cases, the hyperplastic component was MSI-H and the adenoma area was MSS. Conclusion: Hyperplastic polyps, even if smaller than 5 mm, are precancerous lesions bearing different mutations. GRHPs with predominant KRAS mutations and MVHPs and MPHSs with predominant BRAF mutations are precancerous. Although the molecular investigations for HPP/SP are not necessary the morphological subtyping should be included if the case is diagnosed with HPP/SP as it will be useful for attracting the gastroenterologist’s attention.

Background: P-glycoprotein (P-gp) transports many chemicals that vary greatly in their structure and function. It is normally expressed in renal proximal tubular cells. We hypothesized that P-gp expression influences light chain excretion. Therefore, we investigated whether renal tubular P-gp expression is altered in patients with plasma cell disorders. Methods: We evaluated renal biopsy specimens from patients with plasma cell disorders (n = 16) and primary focal segmental glomerulosclerosis (the control group, n = 17). Biopsies were stained with an anti-P-gp antibody. Loss of P-gp expression was determined semi-quantitatively. Groups were compared for loss of P-gp expression, and clinical variables. Results: P-gp expression loss was more severe in patients with plasma cell disorders than it was in those with glomerulonephritis (P = 0.021). In contrast, clinical and histological parameters including serum creatinine, level of urinary protein excretion, and interstitial fibrosis/tubular atrophy grade were not significantly different between the groups. P-gp expression loss increased with age in patients with plasma cell disorders (P = 0.071). This expression loss was not associated with serum creatinine, the level of urinary protein excretion or the interstitial fibrosis/tubular atrophy grade. There was no significant association between the severity of P-gp expression loss with the types and serum levels of light chains, isotypes and serum immunoglobulin levels. Conclusion: Renal tubular P-gp expression is significantly down-regulated in patients with plasma cell disorders characterized by nephrotic range proteinuria. Additional studies are needed to determine whether reintroduction of renal tubular P-gp expression would mitigate the proximal tubular injury that is caused by free-light chains.

The introduction of tumor necrosis factor-alpha (TNF-α)-targeting drugs has given new opportunities in the treatment of various inflammatory rheumatic diseases and has been the most important development in the treatment of spondyloarthritis (SpA). However, the increasing use and longer follow-up periods of treatment also pose risks of developing various adverse effects ranging from common ones including infections to uncommon renal complications. This report describes a case of infliximab-induced focal segmental glomerulosclerosis (FSGS) in a 40-year-old female patient with ankylosing spondylitis (AS) who presented with asymptomatic proteinuria and microscopic hematuria. To the best of our knowledge, this is the second reported case of FSGS attributed to infliximab (IFX). A review of the English literature was conducted for cases of possible IFX-associated renal disorders in patients with SpA and SpA spectrum diseases. In this respect, the reported renal pathologies were IgA nephropathy, crescentic glomerulonephritis, acute renal artery occlusion, acute tubulointerstitial nephritis (ATIN), FSGS, and membranous glomerulopathy. Furthermore, partial or complete resolution was reported after cessation of therapy. In conclusion, although renal complications of TNF inhibitors (TNFi) are uncommon, spot urine evaluation may be recommended in the follow-up of patients treated with TNFi.

This is the 48th installment of a series that will highlight one case per publication issue from the bank of cases available online as a part of the American Society of Emergency Radiology (ASER) educational resources. Our goal is to generate more interest in and use of our online materials. To view more cases online, please visit the ASER Core Curriculum and Recommendations for study online at http://www.aseronline.org/curriculum/toc.htm .

Multiple myeloma (MM) is one of the most important clonal malignant plasma cell disorders and renal involvement is associated with poor prognosis. Although there are several reasons for renal impairment in MM, the main cause is the toxic effects of monoclonal proteins. Although cast nephropathy is the best known and unchallenged diagnosis for hematologists and pathologists, the renal effects of monoclonal gammopathy can be various. Monoclonal gammopathy of renal significance was proposed by the International Kidney and Monoclonal Gammopathy Research Group for renal lesions in monoclonal gammopathy in recent years. Renal lesions in monoclonal gammopathy can be grouped as follows: light chain (cast) nephropathy, acute tubular injury/necrosis, tubulointerstitial nephritis, amyloidosis, monoclonal Ig deposition diseases, immunotactoid glomerulopathy, type I cryoglobulinemia, proliferative glomerulonephritis with monoclonal IgG deposits, C3 glomerulopathy with monoclonal gammopathy, and crystal-storing histiocytosis, considering the previous and new terminology. In this study, renal involvement of monoclonal gammopathies, in terms of previous and new terminology, was reviewed.