F. Nguyen

Pigeon circovirus infection: Pathological observations and suggested pathogenesis

Pigeon circovirus infection (PiCV) was diagnosed by light and transmission electron microscopy in 15 birds from five lofts in western France. Histopathological findings were suggestive of primary bursotropism of pigeon circovirus, followed by secondary systemic spread from the bursa of Fabricius, particularly to non-bursal lymphoid organs. The last stage of the disease was associated with various secondary (particularly bacterial) infections. In situ detection of apoptosis in the bursa of Fabricius indicated that PiCV was concomitant with an increase in bursal lymphocytic apoptotic events related to viral infection and leading to severe acquired immunosuppression.

Microvessel density in muscles of dogs with golden retriever muscular dystrophy

Due to the abundance of muscle, intravascular administration seems required for efficient gene or cell therapy of muscular dystrophy. Here, we examined the skeletal muscle microvasculature to assess if it is altered with dystrophin deficiency. Image analysis of capillaries was performed in three muscles of one- to ten-month-old golden retriever muscular dystrophy (GRMD) dogs and compared with healthy controls. In the gracilis muscle (and in the biceps brachii muscle) of 4- to 10-month-old GRMD dogs, the microvessel density (445+/-47 microvessels per mm(2)), the capillary to fiber ratio (111+/-26 capillaries per 100 myofibers), and the mean intercapillary distance (49+/-3 microm), were similar in affected and control dogs. The sartorius cranialis muscle in GRMD dogs showed microvessel depletion and increased intercapillary distance, but unaltered capillary to fiber ratio, relative to the controls. The mean diameter of microvessels and the total vascular area were higher in GRMD muscles than in control ones. In severely affected GRMD muscles at 7-10 months of age, fibrosis was associated with decreased microvessel density, increased intercapillary distance and microvessel diameter, but normal capillary to fiber ratio and total vascular area.

Abstract 85: Prognostic stratification of naturally occurring canine triple negative invasive mammary carcinoma according to IGF1-R and AR expression

Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA Triple negative breast cancer (TNBC) lacking ER-Estrogen Receptor and PR-Progesterone Receptor expression and HER2-Human Epidermal Growth Factor Receptor 2 overexpression, is a highly aggressive and heterogeneous disease for which better understanding and targeted treatments are needed. Insulin-like growth factor-1 receptor (IGF-1R) and androgen receptor (AR) are frequently expressed in TNBC and correlate with prognosis, making them potential candidates for new therapeutic pathways. Dogs spontaneously develop invasive mammary carcinoma with a high prevalence of the triple negative subtype (TNCMC). We therefore aimed to quantify AR and IGF-1R expression in naturally occurring TNCMC and assess their combined prognostic value in terms of overall (OS), specific (SS) and disease-free survivals (DFS). 104 TNCMC were included (ER<10%, PR<10%, HER2<3+ by IHC-immunohistochemistry). Female dogs were followed for at least 2 years after mastectomy. 71 TNCMC were basal-like (CK5/6-Cytokeratin and/or EGFR-Epidermal Growth Factor Receptor positive) and 33 non basal-like (CK5/6 and EGFR negative). IGF-1R expression (clone G11) was quantified using the same scoring system as for HER2 in breast cancer. AR expression (clone SP107) was considered positive if there were at least 1% positive tumor nuclei. 47/104 (45%) TNCMC overexpressed IGF-1R (3+ IHC score). 40/104 (38%) TNCMC were AR positive. IGF-1R overexpression positively correlated with lymphovascular invasion (LVI) (p=0.01). AR expression negatively correlated with LVI (p<0.01). IGF-1R and AR IHC expression stratified TNCMC into 3 groups with different outcomes: AR positivity defined the TN Luminal-AR group (n=40); among AR-negative cases, IGF-1R scores 2+ and 3+ defined the TN IGF-1R+ group (n=54); other cases were defined as “all negative”: TN All-Neg group (n=10). By univariate analysis, OS significantly differed (p=0.02) among groups with hazard ratio (HR) of 0.8 (95% CI 0.3-1.6) for the TN All-Neg group and 1.7 (1.1-2.6) for the TN IGF1R+ group compared to the TN Luminal-AR group. SS was also significantly different (p<0.01) with respective HR of 0.6 (0.2-1.9) in the AllNeg group and 2.3 (1.3-4.0) in the IGF-1R+ group. DFS, defined as the interval from mastectomy to the first local recurrence or lymph node metastasis, was shorter in the TN IGF-1R+ group (HR=2.3; 95% CI 1.2-4.1; p=0.02) than in the TN Luminal-AR group. By multivariate analysis, the stratification of TNCMC according to AR and IGF-1R expression was an independent prognostic factor associated with DFS and SS with grade, LVI and completeness of excision as covariates. IGF-1R overexpression and AR positivity are common in canine triple-negative invasive mammary carcinoma. Our result revealed the value of using a combination of IGF-1R and AR for the prognostic stratification of TNCMC with a potential translational application to human triple negative breast cancer. Citation Format: Laetitia Jaillardon, Delphine Loussouarn, Jerome Abadie, Brigitte Siliart, Mario Campone, Frederique Nguyen. Prognostic stratification of naturally occurring canine triple negative invasive mammary carcinoma according to IGF1-R and AR expression. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 85. doi:10.1158/1538-7445.AM2014-85

Abstract P2-05-05: Canine invasive mammary carcinoma as a spontaneous model for insulin-like growth factor-1 receptor-overexpressing triple negative breast cancer

Background: Dogs spontaneously develop invasive mammary carcinoma with a high prevalence of the triple-negative subtype, making this model relevant for the investigation of new therapeutic pathways. Insulin-like growth factor-1 receptor (IGF-1R) is extensively involved in malignant transformation, proliferation and metastasis in human breast cancer and multiple clinical trials have used IGF-1R inhibitors with encouraging results. Aims: To quantify IGF-1R expression in canine triple-negative invasive mammary carcinoma (TN-CMC) and assess its prognostic value (overall, specific and disease-free survival). To validate the dog as a spontaneous animal model for preclinical trials targeting IGF-1R in triple-negative breast cancer. Material and methods: 104 triple-negative canine invasive mammary carcinomas (Estrogen receptor negative, Progesterone receptor negative, not HER2 overexpressing) were included. Bitches were followed for at least 2 years after mastectomy. TN-CMC were classified as basal-like (Cytokeratin-CK 5/6 positive and/or Epidermal Growth Factor Receptor-EGFR positive) and non-basal-like (CK 5/6 and EGFR negative). IGF-1R expression (clone G11) was quantified using the same scoring system as for HER2 in breast cancer. Results: 68.3% (n = 71/104) of the TN-CMC were classified as basal-like and 31.7% (n = 33/104) as non-basal-like. 45.2% (n = 47/104) of TN-CMC overexpressed IGF-1R (score 3+), of which 70.2% (n = 33/47) were basal-like and 61.7% (n = 29/47) were grade III. Univariate and multivariate analyses revealed that IGF-1R overexpression (score 3+) was associated with significantly shorter overall, specific and disease-free survivals (median: 163, 332 and 278 days respectively) than weak (score 1+) IGF-1R expression (median: 842 days, not achieved and 1011 days respectively). Conclusion and perspectives: IGF-1R overexpression is common and related to a poor outcome in canine triple-negative invasive mammary carcinoma. Preclinical studies using the dog as a spontaneous animal model for triple-negative breast cancer could be considered to investigate new therapies targeting IGF-1R. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P2-05-05.