Objective: To investigate the clinical and pathological characteristics of breast cancer with HER2 low expression. Methods: The data from 3 422 patients with invasive breast cancer which archived in Peking Union Medical College Hospital between April 2019 and July 2022 were retrospectively reviewed. Among them, 136 patients were treated with neoadjuvant chemotherapy. The tumor size, histological type, tumor differentiation, lymph node metastasis, Ki-67 index, the status of estrogen receptor, progesterone receptor and HER2 as well as pathological complete response (pCR) rate were collected. Results: The HER2 status of 3 286 patients without neoadjuvant therapy, 616 (616/3 286, 18.7%) score 0, 1 047 (1 047/3 286, 31.9%) score 1+, 1 099 (1 099/3 286,33.4%) score 2+ and 524 (524/3 286,15.9%) score 3+ by immunohistochemistry (IHC). Among the 1 070 IHC 2+ cases, 161 were classified as HER2 positive by reflex fluorescence in situ hybridization (FISH) assay. In our cohort, 1 956 cases of HER2-low (IHC 1+ and IHC 2+/FISH-) breast cancer were identified. Compared to the HER2 IHC 0 group, HER2-low tumors more frequently occurred in patients with hormone receptor (HR) positive (P<0.001), Ki-67 index below 35% (P<0.001), well or moderate differentiation (P<0.001) and over the age of 50 (P=0.008). However, there were no significant differences in histological type, tumor size, and lymph node metastasis between HER2-low and HER2 IHC 0 group. For patients who had neoadjuvant therapy, the pCR rate in the patients with HER2-low was lower than those with HER2 IHC 0 (13.3%, 23.9%), but there was no significant difference. Although HER2-low breast cancers showed a slightly lower pCR rate than HER2 IHC 0 tumors, no remarkable difference was observed between tumors with HER2-low and HER2 IHC 0 regardless of hormone receptor status. Conclusions: The clinicopathological features of HER2-low breast cancers are different from those with HER2 IHC 0. It is necessary to accurately distinguish HER2-low breast cancer from HER2 IHC 0 and to reveal whether HER2-low tumor is a distinct biological entity.
目的： 探讨HER2低表达乳腺癌的特征。 方法： 收集北京协和医院2019年4月至2022年7月3 422例存档的浸润性乳腺癌患者临床资料，其中包括具有完整新辅助化疗信息的患者136例。所分析的指标包括年龄、雌激素受体和孕激素受体状态、HER2状态、Ki-67阳性指数、组织学分型、肿瘤分化、肿瘤大小及淋巴结转移，以及病理完全缓解（pathologic complete response，pCR）率。 结果： 在未接受新辅助治疗的3 286例乳腺癌中，检出免疫组织化学（IHC）0者616例（616/3 286，18.7%）、IHC 1+者1 047例（1 047/3 286，31.9%）、IHC 2+者1 099例（1 099/3 286，33.4%）及IHC 3+者524例（524/3 286，15.9%）。在IHC 2+组中1 070例乳腺癌进行荧光原位杂交（FISH）检测，其中HER2扩增者161例。在本队列中，HER2低表达（IHC 1+和IHC 2+/FISH-）乳腺癌共计1 956例。与HER2 IHC 0组相比，HER2低表达好发于50岁以上（P=0.008）、激素受体阳性（P<0.001）、Ki-67阳性指数<35%（P<0.001）及非低分化（P<0.001）的乳腺癌中。而组织学分型、肿瘤大小及淋巴结转移情况等临床病理特征在HER2低表达和HER2 IHC 0组中差异无统计学意义（P>0.05）。新辅助化疗后，HER2低表达组的pCR率低于HER2 IHC 0组（分别为13.3%和23.9%），但差异无统计学意义（P>0.05）；尽管按激素受体状态分类，也都观察到HER2低表达组的pCR率略低于HER2 IHC 0组，但差异仍无统计学意义（P>0.05）。 结论： HER2低表达组乳腺癌的临床病理特征不同于HER2 IHC 0组。准确区分HER2低表达和HER2 IHC 0并探索其是否为一个独立的生物学实体是有必要的。.

BACKGROUND: Colorectal cancer (CRC) is a major public health problem and one of leading cancer related death all over the world. One of the prognostic parameters that play a role in different types of cancer is HER2. However, the role of HER2 in CRC and its relation with clinicopathological features and survival is conflicting. We hypothesize that HER2 has different patterns of expression in CRC which may affect the prognosis of patients.
METHODS: We studied sixty specimens of colorectal carcinoma for HER2 immunohistochemistry and gene amplification and correlate it with clinicopathological features and patients` survival.
RESULTS: Our data showed that negative HER2 expression was statistically associated with female gender (P = 0.010) and low & intermediate tumor budding (P = 0.030). There was a statistically significant relation between HER2 IHC and HER2 FISH amplification (P=0.000). Although neither HER2 immunoexpression and FISH amplification showed significant relation with overall survival nor disease free survival, HER2 amplified CRCs tended to have a worse survival compared with negative CRCs (40 months versus 50 months). The presence of male gender, lymphovascular invasion, nodal metastasis and distant metastasis (P = 0.013, 0.006, 0.006 and 0.000 respectively) were significantly statistically associated with poor overall survival. The presence of tumor grade III and high tumor budding (P = 0.035 and 0.007 respectively) were significantly statistically associated with shorter disease free survival.
CONCLUSIONS: Our results showed that HER2 IHC 3+ staining is highly predictive of HER2 gene amplification in colorectal carcinomas. There is a tendency towards poorer prognosis in amplified HER2 CRC cases.

Histopathological assessment of tissue samples after prolonged formalin fixation has been described previously, but currently there is only limited knowledge regarding the feasibility of molecular pathology on such tissue. In this pilot study, we tested routine molecular pathology methods (DNA isolation, DNA pyrosequencing/next-generation sequencing, DNA methylation analysis, RT-PCR, clonality analysis and fluorescence in situ hybridization) on tissue samples from 11 tumor entities as well as non-neoplastic brain tissue from 43 body donors during the gross anatomy course at Ulm University (winter semester 2019/20 and 2020/21). The mean post mortem interval until fixation was 2.5 ± 1.6 days (range, 1-6 days). Fixation was performed with aqueous formaldehyde solution (formalin, 1.5-2%). The mean storage time of body donors was 12.8 ± 5.6 months (range, 7-25 months). While most diagnostic methods were successful, samples showed significant variability in DNA quality and evaluability. DNA pyrosequencing as well as next-generation sequencing was successful in all investigated samples. Methylation analyses were partially not successful in some extend due to limited intact DNA yield for these analyses. Taken together, the use of prolonged formalin-fixed tissue samples from body donors offers new avenues in research and education, as these samples could be used for morpho-molecular studies and the establishment of biobanks, especially for tissue types that cannot be preserved and studied in vivo. Pathological ward rounds, sample collection, and histopathological and molecular workup have been integrated in the gross anatomy course in Ulm as an integral part of the curriculum, linking anatomy and pathology and providing medical students early insight into the broad field of (molecular) pathology.

Human epidermal growth factor receptor 2 (HER2)-low breast cancer has emerged as a subtype of breast cancer, defined by HER2 1+/2+ in immunohistochemistry (IHC) and absence of ERBB2 gene amplification on fluorescence in situ hybridization (FISH). Recent trials showed marked response of HER2-low breast cancer to novel anti-HER2 antibody-drug-conjugates. Data on characteristics of HER2-low breast cancer subtype is limited. Real-world data from the Anatomic Pathology Department of Hotel-Dieu de France, spanning 2017-2023, was retrospectively collected. HER2-positive patients were excluded to compare HER2-low to HER2-zero breast cancer subtypes. Clinicopathological characteristics between the groups were compared using a Chi-Squared test. Out of 1195 patients, we observed 341 (28.5 %) HER2-low breast cancers cases. HER2-positive breast cancer cases (n = 178; 14.9 %) were excluded. There was no significant difference in age and sex between HER2-low and HER2-zero group (p = 0.33 and 0.79, respectively). HER2-low breast cancer was associated with positive estrogen receptor status and positive progesterone receptor status (p < 0.001 and p = 0.01, respectively). Ductal adenocarcinomas were more commonly observed in HER2-low group (p < 0.001). When stratified by hormone (HR) status, 87.4 % of patients had HR-positive status and 12.6 % were HR-negative. Among the HR-negative group, HER2-low tumors tended to show lower proliferation index compared to HER2-zero tumors (25%vs.10 %, p = 0.04). This study showed that HER2-low is distinct from HER2-zero and is common among patients with breast cancer. Clinicopathological features such as histological type differ between HER2-zero and HER2-low breast cancer. Within HR-negative breast cancer, those with low HER2 expression exhibit a less aggressive profile compared to HER2-zero tumors.

This study investigated the clinicopathological, immunohistochemical, and molecular features of primary leptomeningeal melanocytic neoplasms (LMNs). Twelve LMN cases were retrospectively reviewed. We performed Fluorescence in-situ hybridization (including a 4-probe FISH assay with CDKN2A and MYC assay) and Next-Generation sequencing analyses on available cases. Histologically, 2 tumours were classified as melanocytomas (MC), 2 as intermediate-grade melanocytomas (IMC), and 8 as leptomeningeal melanomas (LMM). Two rare cases of LMM were associated with large plaque-like blue nevus. One MC case was associated with Ota. Ten cases (83.3%) showed melanocytic cells with benign features diffusely proliferating within the meninges. The Ki-67 in three categories differed (MC 0-1%, IMC 0-3%, LMM 3-10%). 57.1% of LMM cases (4/7) were positive for FISH. Nine of 10 tumours harboured activating hotspot mutations in GNAQ, GNA11, or PLCB4. Additional mutations of EIF1AX, SF3B1, or BAP1 were found in 40%, 30%, and 10% of tumours, respectively. During the follow-up (median = 43 months), 5 LMM patients experienced recurrence and/or metastasis, 3 of them died of the disease and the other 2 are alive with the tumour. Our study is by far the first cohort of LMN cases tested by FISH. In addition to morphological indicators including necrosis and mitotic figures, using a combination of Ki-67 and FISH helps to differentiate between IMC and LMM, especially in LMM cases with less pleomorphic features. SF3B1 mutation is first described in 2 cases of plaque-type blue nevus associated with LMM. Patients with SF3B1 mutation might be related to poor prognosis in LMN.

Recently there is much debate in the scientific community over the impact of the food matrix on prebiotic efficacy of inulin-type fructans. Previous studies suggest that prebiotic selectivity of inulin-type fructans towards bifidobacteria is unaffected by the food matrix. Due to differences in study design, definitive conclusions cannot be drawn from these findings with any degree of certainty. In this randomised trial, we aimed to determine the effects that different food matrices had on the prebiotic efficacy of inulin-type fructans following a standardised 10-day, 4-arm, parallel, randomised protocol with inulin either in pure form or incorporated into shortbread biscuits, milk chocolate or a rice drink. Similar increases in Bifidobacterium counts were documented across all four interventions using both fluorescence in situ hybridisation (pure inulin: +0.63; shortbread: +0.59; milk chocolate: +0.65 and rice drink: +0.71 (log10 cells/g wet faeces) and 16S rRNA sequencing quantitative microbiome profiling data (pure inulin: +1.21 × 109; shortbread: +1.47 × 109; milk chocolate: +8.59 × 108 and rice drink: +1.04 × 109 (cells/g wet faeces) (all P ≤ 0.05). From these results, we can confirm that irrespective of the food matrix, the selectivity of inulin-type fructans towards Bifidobacterium is unaffected, yet the compositional make-up of the food matrix may have implications regarding wider changes in the microbiota.

Genomic instability is an important biomarker in the progression of cervical carcinoma. DBD-FISH (DNA breakage detection-fluorescence in situ hybridization) is a sensitive method that detects strand breaks, alkali-labile sites, and incomplete DNA excision repair in cells of the cervical epithelium. This technique integrates the microgel immersion of cells from a vaginal lesion scraping and the DNA unwinding treatment with the capacity of FISH integrated into digital image analysis. Cells captured within an agarose matrix are lysed and submerged in an alkaline unwinding solution that generates single-stranded DNA motifs at the ends of internal DNA strand breaks. After neutralization, the microgel is dehydrated and the cells are incubated with DNA-labeled probes. The quantity of a hybridized probe at a target sequence corresponds to the measure of the single-stranded DNA produced during the unwinding step, which is equivalent to the degree of local DNA breakage. DNA damage does not show uniformly throughout the entire DNA of a cell; rather, it is confined to specific chromosomal sites. In this chapter, an overview of the technique is supplied, focusing on its ability for assessing the association between DNA damage in specific sequences and in the progressive stages of cervical carcinoma.

BACKGROUND: Perivascular epithelioid cell tumors (PEComas) encompass a group of rare mesenchymal neoplasms, with dual melanocytic and muscular differentiation. Hepatic PEComas are rare and difficult to diagnose, and their behavior is still unclear.
METHODS: Herein, we report a total of five cases of hepatic and perihepatic PEComas over a period of the last 5 years from our and collaborating center\'s archive. A detailed histological evaluation was done. A comprehensive panel of immunohistochemical stains was used and fluorescence in-situ hybridization analysis was performed for the TFE3 gene using break-apart probes.
RESULTS: All these patients were women, with an average age of presentation of 44 years. The lesions were in the right hepatic lobe: three cases, the left hepatic lobe: one case, and gastrohepatic ligament: one case. The preoperative clinicoradiological diagnoses were hepatocellular carcinoma (HCC), focal nodular hyperplasia, hemangioma, metastasis, and gastrointestinal stromal tumor, respectively. Surgical excision was performed in four cases with no further adjuvant therapy. Histopathological examination and subsequent immunophenotyping revealed a diagnosis of PEComa. Fluorescence in-situ hybridization analysis was performed for TFE3 gene rearrangement in four cases.
CONCLUSIONS: This series highlights the fact that accurate histological diagnosis of hepatic or perihepatic PEComas is important to prevent unnecessary aggressive treatment, unlike primary hepatocellular carcinomas or hepatoid/epithelioid metastatic tumors.

Williams-Beuren syndrome is a rare genetic disease (1/20 000) characterized by a microdeletion at 7q11.23 encompassing about 28 genes, including the elastin gene, ELN. It is a sporadic disease in the majority of cases. Easily identifiable in childhood, this developmental disorder associates suggestive face dysmorphism, cardiac defect, psychomotor retardation and specific behavioural and cognitive profile. We conducted a retrospective study of 11 patients with Williams-Beuren syndrome whose data were collected in the Genetics Department of the Mohammed VI University Hospital of Marrakech. The average age of patients was 6.05 years (SD=6.56; interquartile range=5), with a female predominance (64%; 7/11 patients). Almost all patients were mentally retarded and the diagnosis was confirmed in 100% (11) of patients using fluorescence in situ hybridisation (FISH).

OBJECTIVE: TFE3-rearranged renal cell carcinomas (RCCs) harbor gene fusions between TFE3 and 1 of many partner genes. MED15::TFE3 fusion RCC is rare, often cystic, and easily misdiagnosed.
METHODS: This study aimed to characterize 2 cases of MED15::TFE3 fusion RCC with extensive cystic change using fluorescence in situ hybridization and targeted RNA sequencing.
RESULTS: Both patients were young adult women aged 29 and 35 years. Radiologically, both presented with a cystic Bosniak category II renal lesion. The cysts measured 9.3 cm and 4.8 cm in greatest dimension. Both patients underwent cyst enucleation, and neither had tumor recurrence or metastasis at 26 and 6 months of follow-up, respectively. Microscopically, both tumors were entirely cystic, with thick, fibrous cystic walls lined by small clusters of cells with clear to eosinophilic cytoplasm and uniform, round nuclei with inconspicuous nucleoli. There were also small aggregations of similar clear cells within the cystic walls. Foci of basement membrane-like material depositions were noted in 1 case; calcifications were observed in both cases. Both cases demonstrated nuclear positivity for PAX8 and TFE3 and cytoplasmic staining for Melan-A; HMB45, CAIX, and CK7 were negative. Fluorescence in situ hybridization revealed that both tumors were positive for TFE3 rearrangements. RNA sequencing identified MED15::TFE3 gene fusions in both cases.
CONCLUSIONS: The main differential diagnosis of MED15::TFE3 fusion RCC includes multilocular cystic renal neoplasm of low malignant potential and atypical renal cysts. Molecular confirmation of TFE3 fusion is essential for establishing the correct diagnosis.