Perianal basal cell carcinoma: a common cancer in an uncommon location

This is a case of a perianal basal cell carcinoma, a common skin cancer in an unusual location. Our patient is a 67-year-old male with a perianal lesion. He first noticed this painless lesion 5 years prior to presentation and was having fecal incontinence and weight loss. He had a fully encompassing ulcerated lesion involving the entirety of the anal margin. We performed a biopsy that returned on pathology as a basal cell carcinoma. Due to the size of the lesion and his current nutritional status, it was determined to be unresectable. We were able to provide him with a diverting colostomy to address his incontinence and this allowed the patient to recover enough to undergo treatment with radiation (total of 5400 cGy). To our knowledge, this is the largest perianal basal cell carcinoma reported in the literature and an example of combining palliative surgery and radiation as a treatment option.

Patient-derived Orthotopic Xenograft Models for Human Urothelial Cell Carcinoma and Colorectal Cancer Tumor Growth and Spontaneous Metastasis

Cancer patients have poor prognoses when lymph node (LN) involvement is present in both high-grade urothelial cell carcinoma (HG-UCC) of the bladder and colorectal cancer (CRC). More than 50% of patients with muscle-invasive UCC, despite curative therapy for clinically-localized disease, will develop metastases and die within 5 years, and metastatic CRC is a leading cause of cancer-related deaths in the US. Xenograft models that consistently mimic UCC and CRC metastasis seen in patients are needed. This study aims to generate patient-derived orthotopic xenograft (PDOX) models of UCC and CRC for primary tumor growth and spontaneous metastases under the influence of LN stromal cells mimicking the progression of human metastatic diseases for drug screening. Fresh UCC and CRC tumors were obtained from consented patients undergoing resection for HG-UCC and colorectal adenocarcinoma, respectively. Co-inoculated with LN stromal cell (LNSC) analog HK cells, luciferase-tagged UCC cells were intra-vesically (IB) instilled into female non-obese diabetic/severe combined immunodeficiency (NOD/SCID) mice, and CRC cells were intra-rectally (IR) injected into male NOD/SCID mice. Tumor growth and metastasis were monitored weekly using bioluminescence imaging (BLI). Upon sacrifice, primary tumors and mouse organs were harvested, weighed, and formalin-fixed for Hematoxylin and Eosin and immunohistochemistry staining. In our unique PDOX models, xenograft tumors resemble patient pre-implantation tumors. In the presence of HK cells, both models have high tumor implantation rates measured by BLI and tumor weights, 83.3% for UCC and 96.9% for CRC, and high distant organ metastasis rates (33.3% detected liver or lung metastasis for UCC and 53.1% for CRC). In addition, both models have zero mortality from the procedure. We have established unique, reproducible PDOX models for human HG-UCC and CRC, which allow for tumor formation, growth, and metastasis studies. With these models, testing of novel therapeutic drugs can be performed efficiently and in a clinically-mimetic manner.

Clopidogrel bisulfate (Plavix) does not increase bleeding complications in patients undergoing rubber band ligation for symptomatic hemorrhoids

BACKGROUND

The incidence of postprocedural bleeding in patients undergoing rubber band ligation (RBL) for symptomatic internal hemorrhoids while taking clopidogrel bisulfate is unknown. To determine the postprocedural bleeding risk of RBL for patients taking clopidogrel compared with age- and sex-matched controls.

MATERIALS AND METHODS

This is a retrospective case-controlled cohort study analyzing data from 2005 to 2013 conducted at a single tertiary care academic center. The study included a total of 80 rubber bands placed on 41 patients taking clopidogrel bisulfate and 72 bands placed on 41 control patients not taking clopidogrel matched for age and sex. The 30-d rates of significant and insignificant bleeding events after RBL were recorded. A bleeding event was considered significant if the patient required admission to the hospital, transfusion of blood products, or additional procedures to stop the bleeding. Insignificant bleeding was defined as passage of blood or clots per rectum with spontaneous cessation and no need for additional intervention.

RESULTS

There was no significant difference in the number of bleeding events per band placed in the clopidogrel group when compared with the control group (3.75% versus 2.78%, P = 0.7387). The rate of significant (2.5% versus 1.39%, P = 0.6244) and insignificant bleeding events (1.25% versus 1.39%, P = 0.9399) was also similar between the two groups. Two significant bleeding events occurred in the clopidogrel group requiring intervention: cauterization in one patient and colonoscopy and transfusion in the other.

CONCLUSIONS

The risk of a bleeding complication after RBL for hemorrhoids does not appear to be increased in patients taking clopidogrel. Our results support the practice of continuing clopidogrel bisulfate in the periprocedural period as the associated risk of thrombosis is greater than the risk of bleeding.

Abstract 1558: The critical role of lymph node stromal cell-derived microvesicles in colorectal cancer metastasis

Introduction: Metastatic disease is responsible for 90% of colorectal cancer (CRC) deaths. Studies suggest that metastasis is closely associated with the presence of CRC tumor-initiating cells (Co-TIC) and their interaction with the lymph node (LN) stromal microenvironment. Prior to developing extra-nodal metastasis, these cells acquire a chemotherapy-resistant phenotype developing genetic alterations making them resistant to conventional treatments. In addition to cell-cell contact and secreted molecules, a recently discovered means of intercellular signaling is the exchange of extra-cellular vesicles. These microvesicles (MVs) carry complex biological information, including mRNA, miRNA, as well as soluble and transmembrane proteins that can affect the behavior of target cells. MVs have been detected in patient specimens with diverse malignancies and may play a role in communication between the LN stromal microenvironment and Co-TIC. We hypothesize that MVs are involved in intracellular trafficking between LN stromal cells and CRC cells promoting tumor formation and distant organ metastasis.

Methods: MVs released by human mesenteric LN stromal cells (LNSC) derived from surgical specimens and the established LN stromal cell line (HK cell) were isolated using differential centrifugation and gradient purification. The MVs were visualized using GFP-HK cell and RFP-HT-29 cell (CRC cell line) and florescence microscopy. The functional properties of LN stromal MVs and their effect on CRC proliferation and metastasis was analyzed using established in vitro co-culture models and a humanized orthotopic intra-rectal (IR) injection mouse model, tracked by bioluminescent imaging (BLI).

Results: A 100,000 g pellet containing MVs derived from LNSC and HK cells have a similar size profile when analyzed by NanoSight. Budding CD63-RFP tagged MVs were released by LNSC and HK cells and uptake by GFP tagged CRC cells was confirmed through time-lapse experiments using deconvoluting microscopy. When HK cell or LN stromal cell-derived MVs were co-cultured with HT-29 cells in vitro, they supported HT-29 cell growth at a similar level as that of HK cell or LN stromal cell conditioned media, respectively. By adding LNSC- or HK-derived MVs to HT-29-Luc cells or patient derived CRC cells (CRC-Pt-Luc cells) in our IR model, we demonstrated that MVs enhanced CRC tumor growth as well as distant organ metastasis in vivo.

Conclusion: MVs isolated from LNSCs traffic between the stromal cells and CRC cells. These MVs promote tumor formation and distant organ metastasis in vivo suggesting that they play a crucial role in the communication between the LN stromal microenvironment and CRC cells. Further analyzing the functional properties of effector MV RNAs may help identify novel targetable candidates for therapeutic strategies that target CRC metastasis using our unique patient derived orthotopic mouse model.

Citation Format: Xin Zhang, Ryan Sullivan, Nathan Hite, Grace Maresh, Linh Hellmers, Zhen Lin, Erik Flemington, Carlos Salomon, Heather Green, David Margolin, Li Li. The critical role of lymph node stromal cell-derived microvesicles in colorectal cancer metastasis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1558.