Immunophenotypes and Tumor Immune Microenvironment in Hepatocellular Carcinoma With Macrotrabecular Massive and Vessels Encapsulating Tumor Clusters.

BACKGROUND/AIM: Recently, vessels encapsulating tumor clusters (VETC) pattern and macrotrabecular massive (MTM) pattern of hepatocellular carcinoma (HCC) have been reported as aggressive histological types. These histological patterns showed an immunosuppressive tumor immune microenvironment (TIME). Since there have been no reports on the differences of these two subtypes simultaneously, this study examined the immunophenotypes and TIME of MTM-HCC and VETC-HCC immunohistochemically. PATIENTS AND METHODS: Seventy-four cases of previously diagnosed HCC, including 32 MTM-HCCs, 21 VETC-HCCs, and 21 conventional HCCs, were enrolled in immunohistochemical analysis. We conducted immunohistochemical analysis. RESULTS: We found that MTM-HCC showed less frequent expression of HepPar-1, which is one of the most common hepatocytic markers. In MTM-HCC, the frequency of high expression levels of Keratin19, carbonic anhydrase (CA) IX, and PD-L1 was higher compared to VETC-HCC and conventional HCC. PD-L1 expression was found in 34.4% of MTM-HCC, 0% of VETC-HCC, and 19.0% of conventional HCC. The rate of PD-L1 expression in MTM-HCC was significantly higher than the others (p=0.0015). PD-L1 expression was significantly associated with epithelial cell adhesion molecules and CA IX expression, which are representative markers of tumor stemness and hypoxic conditions, respectively. The CD8 infiltration in VETC-HCC was significantly lower than that in conventional HCC. CONCLUSION: MTM-HCC had different immunophenotypes and TIMEs compared to HCC with the VETC pattern. Although both had immunosuppressive TIME, the elements forming TIME were quite different. To enhance the immune checkpoint inhibitor efficacy, changing TIME from a suppressive to an active form is essential.

Disappearance of Hepatocellular Adenoma in a Patient with Cornelia de Lange Syndrome after Treatment with Transcatheter Arterial Embolization.

Cornelia de Lange syndrome (CdLS) is a congenital disorder occasionally associated with congenital portosystemic shunt (CPSSs). We herein report a patient with CdLS and CPSS who developed hepatocellular adenomas (HCAs). The patient presented to our hospital for the further investigation of newly diagnosed liver tumors. Imaging findings and pathological examination results indicated that the liver tumors were inflammatory HCAs that subsequently shrank following transcatheter arterial embolization (TAE). Patients with CdLS and CPSS are at risk of developing HCAs, and TAE may be an effective management strategy for HCA in these patients.

Clinicopathologic Features, Genetics, Treatment, and Long-Term Outcomes in Japanese Children and Young Adults with Benign Recurrent Intrahepatic Cholestasis: A Multicenter Study.

BACKGROUND: Few reports of benign recurrent intrahepatic cholestasis (BRIC) have focused on East Asian patients. We describe the clinicopathologic features, genetics, treatment, and outcomes in Japanese BRIC patients. METHODS: We recruited patients with BRIC type 1 (BRIC-1) or 2 (BRIC-2) treated at four pediatric centers and one adult center between April 2007 and March 2022. Demographics, clinical course, laboratory results, molecular genetic findings concerning ATP8B1 and ABCB11 genes, histopathology, and treatment response were examined retrospectively. RESULTS: Seven Japanese patients with BRIC were enrolled (four male, three female; four BRIC-1 and three BRIC-2). The median age at onset for BRIC-1 was 12 years; for BRIC-2, it was 1 month. Intermittent cholestatic attacks numbered from one to eight during the 11 years of median follow-up. Six patients received a mainstream education; only one patient attended special education. None developed cirrhosis. Three with BRIC-1 showed compound heterozygosity for a variant ATP8B1 gene, while one was heterozygous; two BRIC-2 patients showed compound heterozygosity in ABCB11 and one was heterozygous. Liver biopsy specimens obtained during cholestatic attacks showed fibrosis varying from none to moderate; inflammation was absent or mild. Rifampicin administered to three patients for cholestatic attacks was effective in all, as was cholestyramine in two of three. CONCLUSIONS: To our knowledge, this is the first East Asian multicenter study of BRIC patients. Onset age and number of cholestatic attacks varied. Rifampicin and cholestyramine were effective against attacks. No patient developed cirrhosis; most had normal growth and development. The long-term outcomes were satisfactory.

Transcription factor activating enhancer-binding protein 2B expression correlates with invasiveness and prognosis of extramammary Paget's disease.

BACKGROUND: Extramammary Paget's disease (EMPD) is a slowly advancing malignancy that sometimes progresses to the invasion of the dermis, systemic metastases, and death. Although there have been reports that dermal invasion is associated with poor prognosis, no molecular markers of this invasion have been identified thus far. The aim of this study was to identify key molecules for predicting the risk of EMPD dermis invasion. METHOD: We performed microarray screening for three cases of in-situ EMPDs, three cases of invasive EMPDs, and three cases of normal epidermis. We identified a molecule that exhibited a stepwise increase in expression. Further, we analyzed 47 cases of EMPD using immunohistochemical staining (IHC) and examined the correlated clinicopathological findings, including prognosis. RESULT: We examined molecules that showed stepwise differences with invasion. We focused on transcription factor activating enhancer-binding protein 2 B (TFAP2B). Of the 47 EMPD patients, 38 (80.9 %) and 9 (19.1 %) had low and high TFAP2B expression, respectively. TFAP2B expression was significantly correlated with invasion into the dermis, mass formation, and preoperative lymph node metastasis (p = 0.001, 0.042, and 0.033, respectively). The cumulative postoperative recurrence-free rate in the TFAP2B-high expression group was significantly lower than that in the TFAP2B-low expression group (P < 0.001). In univariate analysis of recurrence-free survival, TFAP2B expression was found to be a significant factor (p = 0.006). CONCLUSION: The expression of TFAP2B, which was comprehensively found by microarray screening, may correlate with the invasiveness of EMPD and may be an unfavorable prognostic factor.

Imaging features of ß-catenin-activated hepatocellular adenoma with weak ß-catenin activation: A rare case report.

We report valuable imaging findings in a case of ß-catenin-activated hepatocellular adenoma (ß-HCA) with weak ß-catenin activation. A 40 year-old female presented with a liver tumor in S8 that was incidentally detected on ultrasonography. The tumor showed marked enhancement and early venous drainage into the middle hepatic vein in the arterial phase of contrast-enhanced computed tomography (CT). The tumor revealed slight hypointensity in the hepatobiliary phase of gadolinium ethoxybenzyl diethylenetriamine pentaacetic acid-enhanced magnetic resonance imaging (EOB-MRI). Six months after detection, the tumor had increased in size and a biopsy indicated hepatocellular carcinoma. The tumor was resected and pathologically diagnosed as ß-HCA with weak ß-catenin activation such as exon 3 S45 mutation and exon 7/8 mutation. Marked enhancement in the arterial phase of CT and MRI is a characteristic finding of ß-HCA with weak ß-catenin activation. Furthermore, the degree of ß-catenin activation might determine the signal intensity of ß-HCA in the hepatobiliary phase of EOB-MRI.

Prognostic impact of vessels encapsulating tumor clusters and macrotrabecular patterns in hepatocellular carcinoma.

BACKGROUND: Hepatocellular carcinoma (HCC) shows a high mortality rate. A macrotrabecular (MT) pattern and vessels encapsulating tumor clusters (VETC) pattern have been reported as aggressive histological patterns in HCC. However, their cut-off values have been contentious. METHOD: Nine hundred eighty-five cases of previously diagnosed HCC were enrolled. The percentage areas of the MT and/or VETC pattern with ≥ 5% at every 10% increment were assessed. Clinicopathological analysis including patients' prognosis was conducted. RESULT: One hundred fifty-eight and eighty-four cases were accompanied by 5-49% and ≥ 50% MT components, respectively. Two hundred six and twenty-nine cases had 5-49% and ≥ 50% VETC components, respectively. Cases with these histological patterns in common had aggressive characteristics and worse prognosis compared to cases with none of these patterns. The presence of 5-49% VETC pattern was independent worse prognostic factor in overall survival (P = 0.046). HCCs with the MT pattern and the VETC pattern were significantly accompanied by the VETC pattern and the MT pattern (P < 0.001), respectively. CONCLUSION: As even 5% of the MT pattern and/or VETC pattern affected the prognosis of patients with HCC, the amount of these pattern should be described in pathological reports. This information could be useful in expecting patients' prognosis and providing proper post-operative treatments.

Pancreatic hamartoma: detection of harbouring NAB2::STAT6 fusion gene.

Hamartomas in the pancreas are rare and are often histologically and morphologically similar to solitary fibrous tumours (SFTs). We examined the differences between hamartomas and SFTs at the molecular level. METHODS AND RESULTS: Thirteen patients histopathologically diagnosed with pancreatic hamartoma were included in the study. We also performed STAT6 immunohistochemistry (IHC), which is used in the diagnosis of SFT. Furthermore, for the three cases in which RNA was extracted, reverse transcription polymerase chain reaction to search for NAB2::STAT6 fusions was used. Macroscopically, 13 patients had well-demarcated tumour lesions. Histologically, no islets of Langerhans were observed in the lesions, acinar tissue and ducts were unevenly distributed and elastic fibres were not observed around the ducts by Elastica van Gieson staining. One case contained a lipomatous hamartoma composed mainly of adipose tissue. Seven of the 13 cases demonstrated expression of STAT6 in the nuclei of intervening spindle cells. NAB2::STAT6 fusions were observed in two of the three cases in which RNA was extracted. These two cases also demonstrated STAT6 expression in spindle cells using STAT6 IHC. In one case of lipomatous hamartoma, we did not confirm NAB2::STAT6 fusion or STAT6 expression in STAT6 IHC. CONCLUSION: Of the 13 patients histopathologically diagnosed with hamartoma, two demonstrated NAB2::STAT6 fusions, suggesting the existence of pancreatic hamartomas with molecular-level components identical to those of SFT.

Case Report: A Rare Case of Benign Recurrent Intrahepatic Cholestasis-Type 1 With a Novel Heterozygous Pathogenic Variant of ATP8B1.

Benign recurrent intrahepatic cholestasis type 1 (BRIC1) is a rare autosomal recessive disorder that is characterized by intermittent episodes of jaundice and intense pruritus and caused by pathogenic variants of adenosine triphosphatase phospholipid transporting 8B1 (ATP8B1). The presence of genetic heterogeneity in the variants of ATP8B1 is suggested. Herein, we describe a unique clinical course in a patient with BRIC1 and a novel heterozygous pathogenic variant of ATP8B1. A 20-year-old Japanese man experienced his first cholestasis attack secondary to elevated transaminase at 17 years of age. Laboratory examinations showed no evidence of liver injury caused by viral, autoimmune, or inborn or acquired metabolic etiologies. Since the patient also had elevated transaminase and hypoalbuminemia, he was treated with ursodeoxycholic acid and prednisolone. However, these treatments did not relieve his symptoms. Histopathological assessment revealed marked cholestasis in the hepatocytes, Kupffer cells, and bile canaliculi, as well as a well-preserved intralobular bile duct arrangement and strongly expressed bile salt export pump at the canalicular membrane. Targeted next-generation sequencing detected a novel heterozygous pathogenic variant of ATP8B1 (c.1429 + 2T > G). Taken together, the patient was highly suspected of having BRIC1. Ultimately, treatment with 450 mg/day of rifampicin rapidly relieved his symptoms and shortened the symptomatic period.

A case of ventricular noncompaction associated with heterotaxy and atrioventricular block diagnosed at 15 weeks of gestation using superb microvascular imaging.

We present a case of fetal atrioventricular block, heterotaxy, and ventricular noncompaction observed longitudinally from the first to early second trimesters using B-mode and Doppler imaging, including superb microvascular imaging. At 12 weeks of gestation, the atrial and ventricular rates were 133 and 67 beats/min, respectively, and dextrocardia was noted. At 15 weeks of gestation, detailed sonography revealed ventricular septal defect, interruption of the inferior vena cava, dilated azygos vein, and double-outlet right ventricle. In addition, superb microvascular imaging revealed irregular contours in the anatomical left ventricular wall, indicating prominent trabeculations of the ventricle, which were characteristic findings of ventricular noncompaction. At 21 weeks of gestation, intrauterine fetal death occurred, and the autopsy revealed complex congenital heart disease, including ventricular noncompaction.

Impact of Gleason score of the tumor at the positive surgical margin as a prognostic factor.

Although numerous studies have reported that a positive surgical margin (PSM) is the most important predictive factor for biochemical recurrence (BCR) of prostate cancer (PCa), only a small number of studies have evaluated the predictive value of the Gleason score (GS) of the tumor at the margin in radical prostatectomy (RP). The present study aimed to investigate the preoperative factors that predict PSM and the significant predictive factors for BCR in cases with PSM. In addition, it was examined whether documenting the GS of the tumor at the margin in pathological reports is useful as a predictive factor for BCR. Data of 241 patients with PCa who underwent RP at Kurume University Hospital (Kurume, Japan) between January 2007 and December 2011 were retrospectively reviewed. The median follow-up period was 72 months and 122 patients had at least one PSM. The time to BCR was significantly shorter in patients with PSM than in those with a negative surgical margin. Multivariate analysis demonstrated that >10 ng/ml prostate-specific antigen at diagnosis (P=0.024) and >25% positive core at biopsy (P=0.041) were independent prognostic preoperative factors for PSM. The GS of the tumor at the margin was equal, lower and higher than those of the main tumor in 74 (60.7%), 16 (13.1%) and 32 (26.2%) RPs, respectively. The BCR rates were 35.7, 55.1 and 82.1% in patients whose GS of the tumor at the margin was 6, 7 and 8-10, respectively (P=0.0017). The GS of the tumor at the PSM (P=0.038) and anatomic location of the PSM (P=0.04) were identified as independent prognostic preoperative factors for BCR, whereas the GS of the main tumor and margin length were not. These results suggest that documenting the GS at the margin in pathological reports is useful as a predictive factor for BCR.

Utility of sonic hedgehog and keratin 8/18 immunohistochemistry for detecting ballooned hepatocytes.

AIMS: Ballooned hepatocytes represent liver cell degeneration and are histological hallmarks in the diagnosis of non-alcoholic steatohepatitis, a severe form of non-alcoholic fatty liver disease. However, the identification of ballooned hepatocytes is often difficult, especially in the clinical setting of patients with other chronic liver diseases. In this study, we investigated the utility of immunostaining for positive sonic hedgehog (SHh) protein and negative Keratin 8/18 (K8/18) expression on ballooned hepatocytes. METHODS AND RESULTS: Immunohistochemistry for SHh and K8/18 was evaluated independently by two experienced liver pathologists in non-tumorous liver tissue from 100 cases of resected hepatocellular carcinoma of various aetiology. The degree of hepatocyte ballooning was scored as follows: 0, none; 1, few; 2, many ballooned hepatocytes. These evaluations were performed using routine haematoxylin and eosin (H&E) staining, followed by immunostaining for SHh or K8/18. Using SHh or K8/18 immunostaining combined with H&E staining, the score of ballooned hepatocytes was upgraded in 20 and 19 cases, and downgraded in none and 2 cases, respectively. The percentage of observed agreement for ballooned hepatocytes scoring was 85% and 92%, and the weighted kappa value was 0.806 and 0.893 with SHh or K8/18 immunohistochemistry. Considering the immunohistochemistry results, background liver disease diagnosis was changed in 15 out of 100 cases (15%) evaluated. CONCLUSIONS: SHh and K8/18 immunohistochemistry are useful in detecting ballooned hepatocytes, regardless of background liver disease, and improving pathological diagnosis accuracy.

Expression and significance of laminin receptor in squamous cell carcinoma of the tongue.

BACKGROUND: Laminin receptor is a non-integrin cell-surface receptor that binds laminin present on the basement membrane. It has been reported to be associated with infiltration and metastasis of various malignant tumors. However, no studies regarding tongue cancer have been reported. This study aimed to clarify the role of laminin receptor in squamous cell carcinoma of the tongue. METHODS: We performed immunohistochemical staining of specimens from 66 patients with squamous cell carcinoma of the tongue and assessed laminin receptor expression and clinicopathological factors. As epithelial-mesenchymal transition has been shown to be associated with infiltration and metastasis of malignant tumors, staining for E-cadherin, vimentin, and N-cadherin were also performed. RESULTS: Of 20 patients with postoperative recurrence, 14 exhibited high laminin receptor expression (p = 0.0025). Kaplan-Meier analysis revealed a significantly shorter time to postoperative recurrence for the high laminin receptor expression group than that for the low laminin receptor expression group (p = 0.0008). Based on multivariate analyses for postoperative recurrence, high laminin receptor expression was associated with poor prognosis (high expression vs. low expression; HR =3.19, 95% CI =0.92-11.08; p = 0.0682). There was a correlation between laminin receptor and N-cadherin (p = 0.0089) but not between laminin receptor and E-cadherin (p = 0.369) or vimentin (p = 0.4221). CONCLUSION: These results suggest that high laminin receptor expression is a useful prognostic factor for postoperative recurrence and may be a target for molecular therapy to treat squamous cell carcinoma of the tongue.

Clinicopathological Analysis of Non-B Non-C Hepatocellular Carcinoma Focusing on Cellular Proliferation.

BACKGROUND/AIM: Non-B non-C hepatocellular carcinomas (NBNC-HCCs) are larger than hepatitis virus-related HCCs. We conducted a clinicopathological study of patients who underwent curative NBNC-HCC resection, including proliferative activity assessments, such as nuclear grade and Ki-67 labelling index (LI). MATERIALS AND METHODS: Histopathological findings of 197 patients were examined, including 56 NBNC-HCCs, 45 hepatitis B virus (HBV)-related HCCs (HBV-HCC), and 96 hepatitis C virus (HCV)-related HCCs (HCV-HCC). RESULTS: NBNC-HCCs were significantly larger than HCV-HCCs, but not significantly different from HBV-HCCs. Mitotic counts, nuclear grade, and Ki-67 LI of NBNC-HCCs were not significantly different from those of HCV-HCCs, but were significantly lower than those of HBV-HCCs. Recurrence-free survival was significantly better in the NBNC-HCC group than in the HBV-HCC group in cases with mild liver fibrosis. CONCLUSION: NBNC-HCCs were significantly larger in diameter, but their nuclear grade or Ki-67 LI were not significantly different from those of other HCCs, suggesting that they do not have a higher proliferative activity.

Sphingosine-1-phosphate promotes tumor development and liver fibrosis in mouse model of congestive hepatopathy.

BACKGROUND AND AIMS: Chronic liver congestion reflecting right-sided heart failure (RHF), Budd-Chiari syndrome, or Fontan-associated liver disease (FALD) is involved in liver fibrosis and HCC. However, molecular mechanisms of fibrosis and HCC in chronic liver congestion remain poorly understood. APPROACH AND RESULTS: Here, we first demonstrated that chronic liver congestion promoted HCC and metastatic liver tumor growth using murine model of chronic liver congestion by partial inferior vena cava ligation (pIVCL). As the initial step triggering HCC promotion and fibrosis, gut-derived lipopolysaccharide (LPS) appeared to induce LSECs capillarization in mice and in vitro. LSEC capillarization was also confirmed in patients with FALD. Mitogenic factor, sphingosine-1-phosphate (S1P), was increased in congestive liver and expression of sphingosine kinase 1, a major synthetase of S1P, was increased in capillarized LSECs after pIVCL. Inhibition of S1P receptor (S1PR) 1 (Ex26) and S1PR2 (JTE013) mitigated HCC development and liver fibrosis, respectively. Antimicrobial treatment lowered portal blood LPS concentration, LSEC capillarization, and liver S1P concentration accompanied by reduction of HCC development and fibrosis in the congestive liver. CONCLUSIONS: In conclusion, chronic liver congestion promotes HCC development and liver fibrosis by S1P production from LPS-induced capillarized LSECs. Careful treatment of both RHF and liver cancer might be necessary for patients with RHF with primary or metastatic liver cancer.

Pathological findings of liver steatosis that is difficult to evaluate with ultrasound.

Although new ultrasound (US) methods able to quantitatively assess liver fat content have been recently developed, B-mode US is still the major method for detecting liver steatosis during medical checkups. However, some pathological cases yield false-positive or false-negative liver steatosis results using B-mode US. In addition, histologically, the degree of fat deposits and the size of fat droplets in the liver can affect the sensitivity and specificity of the diagnosis of liver steatosis using B-mode US. As B-mode US evaluation of fatty liver relies on operator expertise, the operator should be aware that there are some cases of liver steatosis that are difficult to evaluate with B-mode US. Here, we describe the pathological findings of liver steatosis that is difficult to evaluate with US.

Neonatal intrahepatic cholestasis caused by citrin deficiency with no hepatic steatosis: a case report.

BACKGROUND: Neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD) is a common form of neonatal jaundice. Histopathological examination of the liver in patients with NICCD typically shows fatty liver, steatohepatitis, and liver fibrosis. Jaundice and fatty liver often improve by 1 year of age. We herein describe a girl who was diagnosed with NICCD based on an SLC25A13 mutation, although no fatty deposits were found on pathologic examination of the liver. CASE PRESENTATION: The patient in this case was a 3-month-old girl. At 2 months of age, she presented with jaundice, discolored stools, and poor weight gain and was found to have hyperbilirubinemia. Cholangiography revealed that she did not have biliary atresia. A laparoscopic liver biopsy was performed, and liver histopathology showed no fatty deposits. Genetic analysis revealed a compound heterozygous mutation in SLC25A13, and she was diagnosed with NICCD. She was given medium-chain triglyceride milk and gained weight. She resumed consumption of normal milk and breast milk, and her stool color improved. She was discharged at 4 months of age with adequate weight gain and a lower total bilirubin concentration. She was in good condition after discharge and showed normal development at the time of outpatient follow-up. CONCLUSIONS: We experienced a case of NICCD in a patient without fatty liver. This case illustrates that the absence of hepatic steatosis in neonatal cholestasis does not rule out NICCD.

Assessing liver stiffness with conventional cut-off values overestimates liver fibrosis staging in patients who received the Fontan procedure.

AIM: Patients who undergo the Fontan procedure for complex congenital heart disease are prone to liver cirrhosis. Liver stiffness (LS) reflects liver fibrosis stage in patients with chronic viral hepatitis; however, its accuracy in predicting liver fibrosis stage in Fontan patients is controversial. We aimed to clarify the correlation between LS and liver fibrosis stage in Fontan patients. METHODS: Fifty-eight Fontan patients were prospectively measured for LS with transient elastography. We undertook liver biopsy, cardiac catheterization, and laboratory tests in 22 of these patients (median age, 14.7 years; range, 9.9-32.1 years) with LS > 11.0 kPa (median, 19.2 kPa; range, 12.2-39.8 kPa); these elevated LS values suggest liver cirrhosis. RESULTS: Histologically, all patients showed mild-to-severe portal and sinusoidal fibrosis but no cirrhosis. Statistically, LS did not predict histological liver fibrosis scores (p = 0.175). Liver stiffness was not correlated with central venous pressure (p = 0.456) or with the hepatic venous pressure gradient (HVPG; p = 0.062), although the p value for HVPG was only slightly above the threshold for significance. CONCLUSIONS: Fontan patients are prone to developing both portal and sinusoidal fibrosis. Liver stiffness could be influenced by HVPG, and using the conventional cut-off values for LS overestimates and overtreats liver fibrosis in these patients.

The Expression of PEDF and its Putative Receptors in Hepatocellular Carcinoma and Background Liver Tissue.

BACKGROUND/AIM: Hepatocellular carcinoma (HCC) remains one of the biggest medical issues. Pigment epithelial-derived factor (PEDF) is a glycoprotein that belongs to the superfamily of serine protease inhibitors. PEDF interacts with its two receptors, adipose triglyceride lipase (ATGL) and laminin receptor (LR). MATERIALS AND METHODS: We conducted immunohistochemical staining for PEDF, LR and ATGL in 151 resected HCCs and their background liver tissues. RESULTS: High expression of LR in HCC was associated with high histological grade and portal vein invasion, while high expression of PEDF in HCC was associated with absence of portal vein invasion. High LR expression in background liver was statistically associated with low serum albumin levels and was an independent prognostic factor of worse outcomes. No cases with more than 5% fatty degeneration in the background liver tissue showed high PEDF expression. CONCLUSION: PEDF/LR/ATGL could be potential biomarkers in HCC and various chronic hepatic disorders.

ER staining levels affect HER2 staining and heterogeneity.

PURPOSE: This study explored the relationship of ER expression levels with HER2 staining properties and heterogeneity and discussed the differences in HER2 assessment caused by the 2018 ASCO/CAP guideline updates from that of the 2013 version. METHODS: HER2-positive breast cancer was divided into three groups of the high hormone receptor expression (LH-high) group, low expression (LH-low) group, or negative (NLH) group to (1) compare differences in the percentage of the HER2 IHC test score of 2 + based on the 2013 ASCO/CAP guideline and in the intratumor heterogeneity of HER2 expression for breast cancer with an IHC score of 3 + among these groups, (2) compare the HER2/CEP17 ratio and the average HER2 copy number, and classified ISH groupings according to the 2018 ASCO/CAP guideline algorithm. RESULTS: (1) Of 244 HER2-positive breast cancers, the cases with a HER2 IHC score of 2 + (n = 54, 22.1%) were significantly more common in the LH-high group (n = 45, P < 0.001). The frequency of heterogeneity was low (n = 25, 10.2%) for the HER2 score of 3 + (n = 190, 77.9%), and significantly higher in the LH-high group (n = 19, 76%, P = 0.002). (2) In a HER2 IHC score of 2 + , Group 2 which is deemed HER2 negative according to the revised 2018 ASCO/CAP guideline was observed in 17 (39.5%) out of 43 cases, of which 16 cases (94.1%) were in the LH-high group. CONCLUSIONS: The LH-high group is a heterogeneous group largely consisting of heterogeneous cases with HER2 IHC scores of 2 + or 3 + . NLH, in contrast, is a homogenous group.