Detection of human epidermal growth factor receptor 2 overexpression in canine anal sac gland carcinoma

Unveiling HER2 immunoexpression in canine hepatoid gland neoplasms: clinicopathological and morphological associations

Canine hepatoid gland neoplasms (HGNs) are significant clinical concerns due to their high prevalence and diverse biological behaviour. Human epidermal growth factor receptor 2 (HER2), a tyrosine kinase receptor implicated in various aspects of tumorigenesis, has been extensively studied in human and animal neoplasms but remains unexplored in HGNs. This study aimed to assess HER2 immunoexpression in canine HGNs and its association with clinicopathological and morphological features. A total of 61 formalin-fixed paraffin-embedded samples, including normal hepatoid glands (n = 10), hepatoid gland adenomas (HGAs, n = 20), hepatoid gland epitheliomas (HGEs, n = 16), and hepatoid gland carcinomas (HGCs, n = 15), were analysed using immunohistochemistry. HER2 expression was scored based on percentage positivity and staining intensity. HER2-positive expression was detected in 50% of HGEs (score 2  +  ) and 73.3% of HGCs, with 36.4% of cases scoring 3   +   . In contrast, all HGAs and normal hepatoid tissues were HER2-immunonegative. Statistical analysis revealed significant differences in HER2 expression among normal and neoplastic hepatoid glands (p < 0.001). Only in HGCs, HER2 expression was significantly associated with tissue invasion (p = 0.007), mitotic count (p = 0.033), and nuclear pleomorphism (p = 0.007). These findings suggest that HER2 may play a role in the progression of malignant HGNs, particularly HGCs. This preliminary study highlights the potential of HER2 as a diagnostic marker and emphasizes the need for further investigation into its prognostic value and role in HER2-targeted therapy for canine HGCs.

Establishment of an experimental model of canine apocrine gland anal sac adenocarcinoma organoid culture using a three-dimensional culture method

Canine apocrine gland anal sac adenocarcinoma (AGASACA) is a rare, malignant tumor in dogs. To date, few cell lines are available and used to establish the current treatment protocols. Organoids are three-dimensional cell cultures derived mainly from stem cells and can reproduce tissue's epithelial structure, function, and genetics, and thus, of great promise in precision medicine. In the current investigation, 10 AGASACA organoid lines were developed from surgically removed tissues of AGASACA-affected dogs and analyzed for comparison with the original tissues. AGASACA organoids were successfully generated from all cases and were positive for CK7, HER2, p53, p63, VEGF, and Ki67, and negative for CK20, consistent with previous reports in dogs and humans. Electron microscopic imaging of AGASACA organoids showed organelles, including numerous granules and fat droplets that characterize apocrine gland cells. AGASACA organoids were tumorigenic in vivo in immunodeficient mice. In addition, treatment of the AGASACA organoids with carboplatin, mitoxantrone, toceranib, and lapatinib revealed different sensitivity profiles among lineages, with carboplatin and lapatinib, in particular, being divided into sensitive and resistant ones. In contrast, mitoxantrone and toceranib showed generally high efficacy in all organoids. In conclusion, our established AGASACA organoids have the potential to be an experimental tool for the development of novel therapies for canine and human apocrine gland adenocarcinoma.

Immunohistochemical Expression of Human Epidermal Growth Factor Receptor 2 and Ki67 in Apocrine Gland Anal Sac Adenocarcinoma

Apocrine gland anal sac adenocarcinoma is an aggressive neoplasm, and surgery remains the treatment of choice, although it is controversial in advanced cases. The prognostic factors are not well established. Human Epidermal Growth Factor Receptor 2 (HER2) is a membrane protein related to tumorigenesis, whereas Ki67 is a nuclear protein related to cell proliferation. Both are potential prognostic markers and therapeutic targets. This study aimed to evaluate the expression of HER2 and Ki67 markers in canine apocrine gland anal sac adenocarcinoma. The tumor samples were divided into four groups: largest tumor diameter less than 2.5 cm, largest tumor diameter greater than 2.5 cm, metastatic lymph nodes, and control group of non-neoplastic anal sacs. Each contained 10 samples. Immunohistochemistry was performed to verify the expression of HER2 and Ki67 markers. Positive HER2 staining was observed in 45% of the neoplastic cases and negative HER2 staining in 100% of the control group. The Ki67 expression had a median of 25% in all groups, except for the control group, which had a median of 8%. The HER2 and Ki67 expression was present in apocrine gland anal sac adenocarcinoma, making them potential therapeutic targets. However, it was not possible to determine the clinical value of either marker.

Effects of trastuzumab emtansine on canine urothelial carcinoma cells in vitro and in vivo

Urothelial carcinoma (UC) is the most common malignancy of the urinary tract in dogs and has aggressive behaviour. Although human epidermal growth factor receptor 2 (HER2) is a known therapeutic target with evidence in canine UC, the efficacy of anti-HER2 antibody drugs remains unknown. This study aimed to investigate the effects of anti-HER2 antibody drugs including trastuzumab and trastuzumab emtansine (T-DM1) on canine UC cell lines in vitro and in vivo. Four canine UC cell lines (Nene, TCCUB, Love, and Sora) were used. In western blotting, HER2 protein expression was observed in all the cell lines. Although both trastuzumab and T-DM1 showed dose-dependent growth inhibitory activity in the cell lines, T-DM1 showed much stronger activity than that of trastuzumab. In flow cytometry analyses with the canine UC cell line (Sora), T-DM1 but not trastuzumab significantly increased the percentages of early and late apoptotic cells in annexin V apoptotic assays and the sub-G1 phase fraction in cell cycle analyses. For the in vivo experiment, the canine UC cells (Sora) were subcutaneously injected into nude mice. Four days after inoculation, trastuzumab, T-DM1, or vehicle was administered intraperitoneally once a week for three times. Tumour volumes were significantly smaller in the T-DM1 group compared to the trastuzumab and vehicle control groups. These findings indicate that T-DM1 exerts a stronger antitumour effect than that of trastuzumab on canine UC cells in vitro and in vivo, possibly by inducing apoptosis due to DM1.

A Preliminary Evaluation of the Prognostic Role of HER-2 and HER-3 Immunohistochemical Expression in Canine Melanomas

Canine melanoma is a malignant and aggressive neoplasm showing clinical, histological, and molecular features similar to the human counterpart. In human medicine, epidermal growth factor receptors (EGFRs) have already been suggested as prognostic markers and potential therapeutic targets in cutaneous melanoma. The aim of this study was to evaluate the expression of HER-2 and HER-3 in canine melanomas by immunohistochemistry and correlate their expression to the clinicopathological parameters of the examined tumors. Thirty-seven canine melanoma samples were recruited. Data regarding signalment and clinical parameters were also collected. The population was composed of 18 cutaneous, 16 oral/mucosal, and three digital/foot pad melanomas. Histopathological investigations were carried out to analyze histological type, ulceration, and mitotic count. On each sample, immunohistochemistry was performed using an anti-Melan-A or anti-Melanoma antigen, i.e., anti-HER-2 and anti-HER-3 antibodies. HER-2 and HER-3 positivity were classified using already established scoring criteria and a statistical analysis was carried out. The results highlighted that HER-2 expression was observed in 48.6% of the samples and HER-3 expression in 18.9%. The highest HER 2 score (3+) was recorded in 16.2% of the samples, while the coexpression of the two receptors was detected in 13.5% of the samples. A statistically significant association (p < 0.05) was observed between the expression of HER-2 and HER-3 and the presence of ulceration in oromucosal tumors. This work confirms the expression of HER-2 and HER-3 in canine melanomas and suggests a putative association with negative prognostic parameters. Further studies are necessary to strengthen these data by increasing the samples size and combining pathological examinations with molecular biology in the investigation of EGFR family receptors.

Clinical Use of Molecular Biomarkers in Canine and Feline Oncology: Current and Future

Molecular biomarkers are central to personalised medicine for human cancer patients. It is gaining traction as part of standard veterinary clinical practice for dogs and cats with cancer. Molecular biomarkers can be somatic or germline genomic alterations and can be ascertained from tissues or body fluids using various techniques. This review discusses how these genomic alterations can be determined and the findings used in clinical settings as diagnostic, prognostic, predictive, and screening biomarkers. We showcase the somatic and germline genomic alterations currently available to date for testing dogs and cats in a clinical setting, discussing their utility in each biomarker class. We also look at some emerging molecular biomarkers that are promising for clinical use. Finally, we discuss the hurdles that need to be overcome in going 'bench to bedside', i.e., the translation from discovery of genomic alterations to adoption by veterinary clinicians. As we understand more of the genomics underlying canine and feline tumours, molecular biomarkers will undoubtedly become a mainstay in delivering precision veterinary care to dogs and cats with cancer.

Shared hotspot mutations in oncogenes position dogs as an unparalleled comparative model for precision therapeutics

Naturally occurring canine cancers have remarkable similarities to their human counterparts. To better understand these similarities, we investigated 671 client-owned dogs from 96 breeds with 23 common tumor types, including those whose mutation profile are unknown (anal sac carcinoma and neuroendocrine carcinoma) or understudied (thyroid carcinoma, soft tissue sarcoma and hepatocellular carcinoma). We discovered mutations in 50 well-established oncogenes and tumor suppressors, and compared them to those reported in human cancers. As in human cancer, TP53 is the most commonly mutated gene, detected in 22.5% of canine tumors overall. Canine tumors share mutational hotspots with human tumors in oncogenes including PIK3CA, KRAS, NRAS, BRAF, KIT and EGFR. Hotspot mutations with significant association to tumor type include NRAS G61R and PIK3CA H1047R in hemangiosarcoma, ERBB2 V659E in pulmonary carcinoma, and BRAF V588E (equivalent of V600E in humans) in urothelial carcinoma. Our findings better position canines as a translational model of human cancer to investigate a wide spectrum of targeted therapies.

Defucosylated Mouse-Dog Chimeric Anti-Human Epidermal Growth Factor Receptor 2 Monoclonal Antibody (H77Bf) Exerts Antitumor Activities in Mouse Xenograft Models of Canine Osteosarcoma

Human epidermal growth factor receptor 2 (HER2) has been studied in many human cancer types, and its overexpression and/or gene mutation contribute to the poor prognosis. Therefore, HER2 is an important therapeutic target in various cancer types, including breast and gastric cancers. We previously developed an anti-HER2 monoclonal antibody (mAb), H₂Mab-77 (mouse IgG₁, kappa), which detects HER2 and dog HER2 (dHER2) with high sensitivity and specificity. In this study, we produced a defucosylated mouse-dog chimeric anti-HER2 mAb (H77Bf), and investigated the reactivity against canine osteosarcoma D-17 cells by flow cytometry. Furthermore, we showed that H77Bf exerted antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity against D-17 cells in vitro and exhibited the potent antitumor activity in vivo. These results suggest that H77Bf exerts antitumor effects against dHER2-expressing canine tumors and could be valuable as part of an antibody treatment regimen for them.

HER2 Overexpression and Cytogenetical Patterns in Canine Mammary Carcinomas

Human epidermal growth factor receptor 2 (HER2) is a tyrosine kinase receptor that promotes tumor cell growth and is implicated in the pathogenesis of human breast cancer. The role of HER2 in canine mammary carcinomas (CMCs) is not clear. Therefore, this study aimed to examine the protein expression and cytogenetic changes of HER2 and their correlation with other clinical-pathological parameters in CMC. We retrospectively selected 112 CMCs. HER2, ER, and Ki67 were assessed by immunohistochemistry. HER2 antibody validation was investigated by immunoblot on mammary tumor cell lines. Fluorescence in situ hybridization (FISH) was performed with probes for HER2 and CRYBA1 (control gene present on CFA9). HER2 protein overexpression was detected in 15 carcinomas (13.5%). A total of 90 carcinomas were considered technically adequate by FISH, and 8 out of 90 CMC (10%) were HER2 amplified, 3 of which showed a cluster-type pattern. HER2 overexpression was correlated with an increased number of HER2 gene copies (p = 0.01; R = 0.24) and overall survival (p = 0.03), but no correlation with ER, Ki67, grade, metastases, and tumor-specific survival was found. Surprisingly, co-amplification or polysomy was identified in three tumors, characterized by an increased copy number of both HER2 and CRYBA1. A morphological translocation-fusion pattern was recognized in 20 carcinomas (22%), with a co-localized signal of HER2 and CRYBA1. HER2 is not associated with clinical-pathological parameters of increased malignancy in canine mammary tumors, but it is suitable for studying different amplification patterns.

Defucosylated mouse‑dog chimeric anti‑HER2 monoclonal antibody exerts antitumor activities in mouse xenograft models of canine tumors

Human epidermal growth factor receptor 2 (HER2) overexpression has been reported in various types of cancer, including breast, gastric, lung, colorectal and pancreatic cancer. A humanized anti-HER2 monoclonal antibody (mAb), trastuzumab, has been shown to improve survival of patients in HER2-positive breast and gastric cancer. An anti-HER2 mAb, H₂Mab-77 (mouse IgG₁, kappa) was previously developed. In the present study, a defucosylated version of mouse-dog chimeric anti-HER2 mAb (H77Bf) was generated. H77Bf possesses a high binding-affinity [a dissociation constant (K_D): 7.5×10⁻¹⁰ M, as determined by flow cytometric analysis] for dog HER2-overexpressed CHO-K1 (CHO/dHER2) cells. H77Bf highly exerted antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) for CHO/dHER2 cells by canine mononuclear cells and complement, respectively. Moreover, administration of H77Bf significantly suppressed the development of CHO/dHER2 ×enograft tumor in mice compared with the control dog IgG. H77Bf also possesses a high binding-affinity (K_D: 7.2×10⁻¹⁰ M) for a canine mammary gland tumor cell line (SNP), and showed high ADCC and CDC activities for SNP cells. Intraperitoneal administration of H77Bf in mouse xenograft models of SNP significantly suppressed the development of SNP xenograft tumors compared with the control dog IgG. These results indicated that H77Bf exerts antitumor activities against dHER2-positive canine cancers, and could be valuable treatment regimen for canine cancers.

Canine Apocrine Gland Anal Sac Adenocarcinoma: A Review

Apocrine gland anal sac adenocarcinoma (AGASAC) is a relatively uncommon tumor in the dog and comprises approximately 17% of perianal malignancies; however, it is one of the most common causes of paraneoplastic hypercalcemia. Clinical signs in affected dogs most commonly are associated with mechanical obstruction caused by the primary tumor or enlarged regional metastatic lymph nodes and the effects of paraneoplastic hypercalcemia when present. Surgical excision of the primary tumor and metastasectomy of affected locoregional lymph nodes is the preferred initial treatment option for most dogs, although radiation therapy and adjuvant chemotherapy are commonly incorporated into multi-modality treatment plans. A significant role for the use of adjuvant chemotherapy has not been clearly demonstrated. Prolonged survival times are possible, especially for dogs with smaller primary tumors and for dogs that undergo further treatments for recurrent disease. In this article, we review the clinical signs, diagnosis, staging, treatment, and prognosis of AGASAC in the dog.

An Anti-HER2 Monoclonal Antibody H2Mab-41 Exerts Antitumor Activities in Mouse Xenograft Model Using Dog HER2-Overexpressed Cells

Overexpression of human epidermal growth factor receptor 2 (HER2) has been reported in a variety of cancer types, including breast, lung, gastric, pancreatic, and colorectal cancers. Trastuzumab, a humanized anti-HER2 monoclonal antibody (mAb), has been shown to provide significant survival benefits in HER2-overexpressing breast cancer and gastric cancer patients. Previously, an anti-HER2 mAb, H₂Mab-41 (IgG_2b, kappa), was developed in our laboratory and its antitumor activity was demonstrated in mouse xenograft models of human colon cancer. The present study aimed to investigate the ability of H₂Mab-41 to induce antibody-dependent cellular cytotoxicity (ADCC) and complement-dependent cytotoxicity (CDC) in dog HER2 (dHER2)-overexpressed cell lines, and thus exert its antitumor activity against dHER2-overexpressed tumors in vivo. Flow cytometry results demonstrated the cross-reactivity of H₂Mab-41 with dHER2. Further evaluation of interaction between H₂Mab-41 and dHER2-overexpressed CHO-K1 (CHO/dHER2) cells indicated moderate binding affinity of H₂Mab-41 toward dHER2, with a dissociation constant (K_D) of 2.6 × 10^-8 M. In vitro analysis revealed that the administration of H₂Mab-41 induced high levels of ADCC and CDC in CHO/dHER2 cells. Furthermore, intraperitoneal administration of H₂Mab-41 in mouse xenograft models of CHO/dHER2 resulted in significant inhibition of tumor development compared to the control mouse IgG. Thus, the findings of the present study demonstrated the in vivo safety and efficacy of H₂Mab-41, highlighting its suitability to be included as a part of a therapeutic regimen for dHER2-expressing canine cancers.

Immunohistochemical Screening of HER2 in Canine Carcinomas: A Preliminary Study

HER2 overexpression has been reported in various human and canine tumours. The aim of this study is to investigate the expression of HER2 protein in different histotypes of canine carcinomas in order to identify potential tumours that could benefit from the HER2-targeted therapy. Eighty-two (82) canine carcinomas (squamous cell, gastro-intestinal, rectal, pulmonary, prostatic, urothelial, and ovarian) from paraffin-embedded samp les were immunohistochemically evaluated. The degree of HER2 expression was scored based on the ASCO/CAP 2018 guidelines. Intestinal carcinomas were those with greater HER2 overexpression (3+) with 81% of positive cases, followed by 42% of rectal carcinomas and 28% of squamous cell carcinomas. These observations suggest that HER2 overexpression could be a driver in the oncogenesis of several types of canine carcinomas and lay the foundations for the identification of different types of canine carcinomas that could benefit from HER2-targeted therapy.

Overexpression of human epidermal growth factor receptor 2 in canine primary lung cancer

Human epidermal growth factor receptor 2 (HER2) overexpression has been reported in various human cancers. HER2-targeted therapies showed clinical responses in humans with HER2-positive tumors. The incidence of canine primary lung cancer (cPLC) is increasing, but there are no effective systemic therapies for dogs with late-stage cPLC. HER2-targeted therapy could be an option for cPLC, but HER2 expression in cPLC remains unknown. We evaluated HER2 expression in cPLC. Immunohistochemical analysis revealed that 3 samples (19%) scored 3+; 8 (50%), 2+; 5 (31%); and 1+ and 0 (0%), 0. Of the cPLC tissues, 69% were HER2 positive (scored ≥2+). These data would lead to further evaluation of the role of HER2 in cPLC as a mechanism of malignancy and therapeutic target.

Cytotoxicity effect of trastuzumab on canine peripheral blood mononuclear cells

BACKGROUND

Trastuzumab is an antibody drug used to treat human epidermal growth factor receptor 2 (HER2) overexpressing human metastatic breast cancer. Antibody-dependent cellular cytotoxicity (ADCC) is considered to be the major mechanism of cytotoxicity of the drug. However, its ability to induce an ADCC response in canine peripheral blood mononuclear cells (PBMCs) is not well established.

AIMS

We aimed to evaluate the ability of trastuzumab in enhancing the cytotoxicity of PBMCs against canine tumor cells.

METHODS

We used canine tumor cell lines isolated from metastatic mammary gland tumors (CHMm and CIPm) and thyroid adenocarcinoma (CTAC). The binding of trastuzumab to the cells was confirmed using flow cytometry analysis. Peripheral blood mononuclear cells obtained from healthy beagles and lymphokine-activated killer (LAK) cells, generated by interleukin-2 (IL-2) stimulation of PBMCs, were used as effector cells. Standard lactate dehydrogenase (LDH) release assay was used to measure the cytotoxicity of the LAK cells against tumor cell lines in the presence of trastuzumab.

RESULTS

Trastuzumab enhanced the cytotoxicity of PBMCs against CHMm. Moreover, LAK cells killed CHMm synergistically in the presence of trastuzumab. However, the presence of trastuzumab did not produce such a synergistic effect when LAK cells acted against CIPm and CTAC.

CONCLUSION

We confirmed the ability of trastuzumab to induce an ADCC response in canine PBMCs and determined its synergistic effect with LAK cells. Although the in vitro system in the present study did not show the induction of trastuzumab-mediated ADCC response against all canine tumor cell lines, the results of this study indicate the potential antitumor activity of trastuzumab in canines.