Novel patient-derived xenograft mouse model for pancreatic acinar cell carcinoma demonstrates single agent activity of oxaliplatin.

BACKGROUND: Pancreatic acinar cell carcinoma (PACC) is a rare malignancy, accounting for <1 % of all pancreatic neoplasms. Very few retrospective studies are available to help guide management. We previously reported the case of a patient with metastatic PACC who achieved prolonged survival following doxorubicin treatment. Personalized treatment was based on molecular and in vitro data collected from primary cells developed from their liver metastasis. We now report the characterization of a patient derived tumor xenograft (PDTX) mouse model that originated from this patient's PACC liver metastasis. METHODS: Fragments of biopsy tissue (5 mm(3)) from PACC liver metastasis were implanted into athymic nude mice. Tumors were grown and passaged from the host mice into new mice to be tested for therapeutic response. Immuno-histochemical (IHC) biomarkers were used to confirm that the PDTX model represents human PACC. The antitumor activities of multiple drugs (5-FU, irinotecan, oxaliplatin, gemcitabine, bevacizumab, erlotinib, doxorubicin and imatinib) were tested. Tumor size was measured over 74 days or until they reached an endpoint volume of ~800 mm(3). Tests to measure serum lipase levels and histological analyses of tumor tissues were also conducted to assess PACC progression and re-differentiation. RESULTS: The model presented here expresses the same IHC markers found in human PACC. In the chemotherapy study, oxaliplatin produced a prolonged durable growth response associated with increased apoptosis, decreased serum lipase levels and increased healthy acinar cells. Bevacizumab also produced a significant growth response, but the effect was not prolonged as demonstrated by oxaliplatin treatment. The other chemotherapies had moderate to little effect, particularly after treatment ceased. Mutations in DNA repair genes are common in PACC and increase tumor susceptibility to oxaliplatin. To explore this we performed IHC and found no nuclear expression of BRCA2 in our model, indicating a mutation affecting nuclear localization. Gene sequencing confirms BRCA2 has a homozygous gene deletion on Exon 10, which frequently causes a protein truncation. CONCLUSIONS: In summary, we report the development and characterization of the first and only preclinical PACC PDTX model. Here we show sustained anti-tumor activity of single agent oxaliplatin, a compound that is more effective in tumors that harbor mutations in DNA repair genes. Our data shows that BRCA2 is mutated in our PACC model, which could contribute to the oxaliplatin sensitivity observed. Further studies on this rare PACC model can serve to elucidate other novel therapies, biomarkers, and molecular mechanisms of signaling and drug resistance.

[A Case of Curative Resection for Advanced Pancreatic Acinar Cell Carcinoma with Liver Metastasis and Involvement of the Superior Mesenteric Artery after Chemoradiotherapy Following Systemic Chemotherapy].

A 52-year-old man was initially diagnosed with an unresectable acinar cell carcinoma of the pancreas with liver metastasis and involvement of the superior mesenteric artery. After 5 courses of systemic chemotherapy(gemcitabine and S-1), the size of the pancreatic tumor had decreased from 31mm to 19mm and the liver metastasis had disappeared. We initiated chemoradiotherapy( CRT: S-1+56 Gy)for further local treatment. After CRT the size of the pancreatic tumor decreased to 13mm and his serum CA 19-9 level decreased from 677.2 U/mL to 38.1 U/mL. After 2months of S-1 administration, we performed subtotal stomach-preserving pancreaticoduodenectomy with D2 lymph node dissection. Histopathological examination revealed that most of the pancreatic cancer was replaced by fibrosis and only a few atypical epithelial cells existed. No cancer cells were found at the surgical margin. The patient remains alive without any signs of recurrence 59 months after the systemic chemotherapy and 51 months after the surgical resection.

Sudden disappearance of the blood flow in a case of pancreatic acinar cell carcinoma.

A 55-year-old man was referred to our hospital for a further examination of a pancreatic cystic tumor with a solid component exhibiting vascularity. A few days later, the patient was admitted with a complaint of sudden severe epigastric pain. Enhanced CT showed the loss of vascularity in the tumor. In particular, contrast-enhanced endoscopic ultrasonography (EUS) clearly demonstrated the disappearance of the blood flow, and a histological examination revealed acinar cell carcinoma with central necrosis. To our knowledge, this is the first case in the literature of acinar cell carcinoma associated with the sudden disappearance of vascularity. In this case, contrast-enhanced harmonic EUS was especially useful for assessing the degree of vascularity.

Contrast-enhanced ultrasonograpic studies on pancreatic carcinoma with special reference to staining and muscular arterial vessels.

Comparative study of contrast-enhanced ultrasonography (CE-US) and histopathology of surgically resected specimens in 13 patients with pancreatic carcinoma. A time intensity curve was used to determine the percentage brightness increase in cancerous and normal regions and the patients were divided into two groups, hyperperfusion, with a percentage brightness increase over 80% (n=6) and hypoperfusion, with an increase of less than 80% (n=7) on CE-US. The hyperperfusion group included well-differentiated tubular adenocarcinoma, adenosquamous cell carcinoma and acinar cell carcinoma, while all 7 patients in the hypoperfusion group had moderately differentiated tubular adenocarcinoma. Immunological staining (α-SMA and anti-CD34) of the resected specimens showed significantly higher microartery count (MAC) in the hyperperfusion group (p<0.005) than in the hypoperfusion group or normal pancreas. In the normal pancreas, the mean vessel diameter was significantly higher (over 100 µm) than in the hyperperfusion group (30 µm; p<0.005). It was concluded that a muscular arterial vessel density of less than 30 µm is an important factor in determining staining degree and carcinoma progression by CE-US in pancreatic carcinoma.

Vascular endothelial growth factor (VEGF) expression and microvascular density in salivary gland tumours.

This study investigates whether salivary tumours with different morphology and evolution also differ in terms of neovascularization and VEGF expression and the prognostic value of the results. Surgical specimens from 45 patients - 8 pleomorphic adenomas (PA), 7 Warthin tumours (WT), 5 basal cell adenomas (BA), 6 carcinomas ex-pleomorphic adenoma (CEPA), 6 mucoepidermoid carcinomas (MEC), 5 acinic cell carcinomas (AC), 4 adenoid cystic carcinomas (ACC) and 4 adenocarcinomas not otherwise specified (ADK NOS) - were immunostained. In malignant salivary tumours, the following mean microvascular density (MVD) values were recorded (± SD = Standard Deviation): 27.61 (SD ± 2.27) in cases with CEPA, 27.08 (DS ± 7.81) in AC and 32.93 (SD ± 7.76) in ADK NOS, with lower values for MEC 24.31(SD ± 2.88) and for ACC 22.13 (SD ± 5.44). For benign tumours, an MVD of 35.71 (SD ± 2.09) was recorded in WT and lower average values in PA (MVD = 14.84; SD ± 4.86) and in BA (MVD = 23.96; SD ± 9.13). MVD did not correlate with the investigated clinicopathological parameters. The VEGF expression is significantly more important (p = 0.001) in malignant salivary tumours as compared with benign ones. The VEGF expression and the microvascularization in salivary gland tumours are important elements to be considered when formulating a diagnosis and assessing case evolutions in patients with such tumours.

Acinic cell carcinoma of the salivary glands: an immunohistochemical study of angiogenesis in 12 cases.

Acinic cell carcinoma (ACC) is the third most common epithelial malignancy of the salivary glands in adults, exhibiting a low-grade malignancy that mainly occurs in the parotid gland and at a relatively younger age than other salivary gland tumors. We performed an immunohistochemically study regarding angiogenesis in ACC, by assessing the CD105+ tumor microvessels density and investigating the VEGF and its receptors VEGFR1 and VEGFR2 expression in tumor samples. The results indicated an active angiogenesis in ACC, with the highest CD105-MVD score recorded in the solid variant. This fact was supported by the reactivity of tumor cells and endothelial blood vessel cells for VEGF and its receptors (VEGFR1 and VEGFR2). Thus, we concluded that in ACC do exist autocrine and paracrine VEGF loops implicated in growth and progression of this kind of salivary gland tumors.

[A case of liver metastasis of pancreatic acinar cell carcinoma treated with S-1 and intra-arterial CDDP combination therapy].

A 55-year-old man underwent a pylorus-preserving pancreatoduodenectomy in August 2006 because of acinar cell carcinoma of the head of the pancreas. Since abdominal CT revealed multiple liver metastases, we started systemic chemotherapy with gemcitabine (1,400 mg/body, day 1, 8, 15/q4w) in October 2006. At the beginning of this treatment, it seemed to be a stable disease, but CT revealed tumor progression in January 2007. Despite the change to oral chemotherapy with S-1 (100 mg/body, day 1-14/q3w), tumors were markedly enlarged in March 2007. Therefore, we selected combination chemotherapy with oral S-1 and hepatic arterial infusion of CDDP (50 mg/body) as third-line. After 6 months of treatment, abdominal CT revealed marked shrinkage of tumors, accompanied by a decrease in AFP level. Though the patient died of hepatic failure in July 2009 (33 months after recurrence), he spent most of his time at home and worked as usual. We suggest that combination chemotherapy with oral S-1 and intra-arterial CDDP can be effective treatments for pancreatic acinar cell carcinoma.

[Hepatic artery ligation for liver metastasis of a acinar cell carcinoma of the pancreas revealed by a nodular panniculitis]. / Ligature de l'artère hépatique pour métastases hépatiques d'un carcinome à cellules acineuses du pancréas révélé par une panniculite nodulaire.

We report the case of a 67-year-old-man presenting with pancreatic acinar cell carcinoma revealed by dermatological manifestations of cytosteatonecrosis and treated by hepatic artery ligation. The pancreatic etiology of these lesions was suspected due to hyperlipasemia, and was confirmed by abdominal computerized tomography showing a pancreatic tumor and multiple liver nodules, and by histological examination of one of these lesions. Because of symptomatic treatment failure, rapid impairment of patient's general condition, and by analogy with the treatment of hepatic metastases of neuroendocrine tumors, hepatic artery ligation was performed. Lipasemia decreased markedly and symptoms disappeared for 45 days. Hepatic artery obstruction may be used for emergency treatment of secreting liver metastases.