Macroscopic Lymph Research Articles

Abstract A17: A versatile mouse-modeling platform for rapid in vivo melanoma studies

Abstract Melanoma accounts for about 1% of skin cancers but causes the majority of skin cancer-related deaths. Despite progress in treating melanoma with immunotherapy and targeted therapy, melanoma patients still suffer from relapse due to resistance to these treatments. A better understanding of the molecular mechanisms that contribute to melanomagenesis and resistance may provide novel avenues for the development of improved treatment strategies. To accelerate the speed, increase the throughput, and lower the cost of delineating such mechanisms in vivo, we developed a novel embryonic stem cell-genetically engineered mouse-modeling (ESC-GEMM) platform. We generated ESC lines harboring twelve combinations of four common driver mutations (BRAF-V600E, NRAS-Q61R, loss of PTEN, loss of CDKN2A) that can be efficiently targeted by recombination-mediated cassette exchange (RMCE) to introduce inducible alleles of interest. Importantly, all of our ESC lines are capable of producing high-contribution chimeras, which exhibit the same melanoma kinetics and overall survival as conventionally bred mice. Thus, our platform offers readily adaptable melanoma models whose melanoma phenotypes range from long latency/low penetrance to aggressive melanoma with complete penetrance. We employed our ESC-GEMM approach to compare the efficiency of gene depletion by conditional knockout, CRISPR/Cas9, or RNAi. We found that CRISPR/Cas9 depletion of Pten on a Braf-V600E background produces fewer melanomas but with nearly the same latency as conditional knockout using the Cre-lox system. Silencing of Pten with inducible shRNA resulted in significantly increased latency as well as in melanomas with a distinct macroscopic appearance and widespread lymph node metastases. While inducible shRNAs allowed us to restore Pten expression in established melanomas, depletion of Pten with inducible CRISPR enabled us to control the number of moles/melanomas by limiting the duration of Cas9 expression. We also used inducible CRISPR to sequentially activate Braf-V600E and delete Pten, which more closely mimics the sequence of events in human melanomas. Interestingly, while sequential introduction of these genetic changes had no effect on the overall survival, a subset of mice developed a significantly greater number of tumors. Finally, we established melanoma cell lines from untargeted chimeras, which can be targeted with Tet-inducible expression cassettes and transplanted into syngeneic hosts. Taken together, we have established a speedy mouse-modeling platform that will stimulate and accelerate in vivo melanoma research, provide a powerful resource to investigate the pathobiology of melanomagenesis, and allow the genetic and pharmacologic evaluation of novel treatments. Citation Format: Ilah Bok, Jordan Reff, Arianna Nenci, Jose G. Gonzalez, Florian A. Karreth. A versatile mouse-modeling platform for rapid in vivo melanoma studies [abstract]. In: Proceedings of the AACR Special Conference on Melanoma: From Biology to Target; 2019 Jan 15-18; Houston, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(19 Suppl):Abstract nr A17.

Impact of macroscopic enlarged lymph node on stage II colorectal cancer prognosis and its potential mechanism

To evaluate the impact of macroscopic enlarged lymph node on the clinicopathological characteristics of stage II colorectal cancer, and to explore the potential mechanism. Clinicopathological data of 116 consecutive patients with stage II colorectal cancer, who underwent colorectal radical resection and were identified as stage II colorectal cancer without mesenteric metastasis by postoperative pathology, in our department between December 2001 and December 2002 were analyzed retrospectively. All the patients were examined by the surgeons with gross appearance to decide the enlarged lymph nodes as metastasis during operation. There were 43 patients with macroscopic enlarged lymph nodes and 73 without such lymph nodes. Survival rate was compared between the two groups. Impact of macroscopic enlarged lymph node on the prognosis of stage II colorectal cancer was analyzed. Structure of macroscopic enlarged lymph node was observed. CK expression in 107 macroscopic enlarged lymph nodes from 43 cases was examined by immunohistochemistry. The 10-year disease-free survival (DFS) of the whole group was 83.5%. The 10-year DFS of patients with macroscopic enlarged lymph nodes was 75.9%, which was significantly lower than 89.3% (P=0.038) of patients without macroscopic enlarged lymph nodes. Univariate analysis showed that macroscopical enlarged lymph node (P=0.038), perioperative blood transfusion (P=0.004), number of retrieved lymph nodes (P=0.016), concomitant disease (P=0.003), and preoperative serum carcinoembryonic antigen (CEA) level (P=0.050) were related to the prognosis of all the 116 patients. Multivariate analysis showed that macroscopical enlarged lymph node (P=0.044), number of retrieved lymph nodes (P=0.021), and perioperative blood transfusion (P=0.032) were independent prognostic factors. Haematoxylin and eosin (HE) staining indicated that enlarged lymph nodes had hyperplasia reaction. Immunohistochemistry showed that among 107 enlarged lymph nodes, 1 had macrometastases, 1 micrometastasis, 4 isolated tumor cell (ITC), and the rest 101 had no positive CK expression. Macroscopic enlarged lymph node indicates a poor prognosis in patients with stage II colorectal cancer.

Papillary Thyroid Cancer, Macrofollicular Variant: The Follow-Up and Analysis of Prognosis of 5 Patients

Objective. The main aim of this study was to comparatively analyze the recurrence and prognosis of this rare variant with the literature by analyzing the follow-up data of 5 patients diagnosed with papillary cancer macrofollicular variant. Methods. The demographic data, radiological and pathological data, and prognostic data of 5 patients who underwent surgery for thyroid cancer and were diagnosed with papillary cancer macrofollicular variant pathologically were retrospectively analyzed. Results. The mean age of patients whose mean follow-up period was determined as 7.2 years was 41, and the male/female ratio was 4/1. All patients underwent total thyroidectomy. The pathology report of 2 patients (40%) revealed macrofollicular variant of papillary microcancer, and 3 patients papillary cancer macrofollicular variant. Central dissection was performed in one patient (20%) due to macroscopic pathologic lymph node and 4 metastatic lymph nodes were reported. Also, locoregional recurrence was present in 3 out of 5 patients (60%). Conclusions. Although an impression of earlier and increased risk of recurrence in papillary carcinoma with macrofollicular variant has been documented, more studies with extensive follow-up times and large populations are required.

Risk factors for peritoneal recurrence in stage II/III gastric cancer patients who received S-1 adjuvant chemotherapy after D2 gastrectomy.

51 Background: Peritoneum is still the most frequent site of the recurrence in stage II/III gastric cancer patients although the survival was improved by S-1 adjuvant chemotherapy. The objective of this retrospective study was to clarify the risk factors of peritoneal recurrence in patients who received S-1 adjuvant chemotherapy. Methods: Peritoneal recurrence free survival (P-RFS) was examined in 100 gastric cancer patients who underwent curative D2 surgery, were diagnosed with stage II or III pathologically, and received adjuvant S-1 between June of 2002 and March of 2011. Uni- and multi- variate analyses were performed to identify risk factors by Cox’s proportional hazard analyses. Results: P-RFS was 64.3% at 3 years and 58.8% at 5 years. A total of 18 patients were diagnosed with peritoneal recurrence. Macroscopic tumor diameter, depth of tumor invasion, and lymph node metastasis were the significant factors by univariate analysis, while tumor diameter and lymph node metastasis were the only significant independent risk factors by multivariate analysis. Conclusions: The macroscopic tumor diameter and lymph node metastasis were the most important risk factors for P-RFS. When patients had these risk factors, S-1 was not sufficient to inhibit peritoneal recurrence. When developing a novel adjuvant chemotherapy targeting peritoneal metastasis in the future, clinical trials should be limited to these patients.

Relationships between estrogen receptor co-regulators and intrinsic subtypes in breast cancer.

Abstract Abstract #603 Background: Gene expression profiling has characterised breast cancers into distinct subtypes largely based on the ER, PR and HER2/neu receptor status (i.e., luminal A, luminal B, HER2/neu over-expressing and basal-like groups). This study aims to investigate relationships between expression levels of genes representing these receptors i.e., ESR1, ESR2, PGR and ERBB2, and selected estrogen receptor co-activator genes (NCOA3, CREBBP) and co-repressor genes (NCOR1 and NCOR2). We also sought to identify whether these co-regulator genes were differentially expressed across subtype, related to patient outcome or known prognostic factors.
 Materials and Methods: Using quantitative real-time PCR, we measured mRNA expression in sixty primary breast tumors and ten normal mammary glands. Relationships between gene expression levels and clinicopathological parameters, intrinsic subtype and clinical outcomes were analysed using Pearson's correlation coefficient, student t-test, ANOVA, Kaplan-Meier survival curves and Cox's proportional hazards model. P<0.05 was considered significant.
 Results: Statistically significant correlations were observed between CREBBP expression and ESR1 (r =0.324); ESR2 (r=0.387); PGR (r=0.397); and ERBB2 (r=0.306). CREBBP also correlated with NCOA3 (r=0.447), a steroid receptor co-activator previously shown to be over-expressed in breast cancers; and was differentially expressed in the luminal B subtype compared to the others (P<0.001). An increase in tumour stage and NCOA3 expression was associated with shorter overall survival (Log Rank; P=0.009 and P=0.043). Prognostic significance of these parameters remained after multivariate analysis. We found no correlation between co-regulator expression and age at diagnosis, macroscopic tumour size and lymph node status.
 Discussion: These findings demonstrate a relationship between CREBBP, breast cancer subtype, and the expression of genes known to be prognostic indicators or indicators of treatment response in breast cancer. Further investigations are required to establish how co-regulator expression influences these intrinsic groups. Citation Information: Cancer Res 2009;69(2 Suppl):Abstract nr 603.

Clinicopathologic characteristics of gastric cancer patients who underwent noncurative gastrectomy with long-term survival

To demonstrate clinicopathologic characteristics of gastric cancer patients who underwent noncurative gastrectomy with long-term survival. We retrospectively reviewed 202 advanced gastric cancer patients who underwent noncurative gastrectomy. The long-term survivors who survived for more than 3 years comprised four of 65 patients with a residual tumor in the peritoneum, one of 50 patients with a residual tumor from lymph node metastasis, three of 41 patients positive for the resected margin (M-factor) and 17 of 153 patients with free intraperitoneal cancer cells (Cy-factor). Multivariate analysis indicated that independent indicators affecting survival were lymph node metastasis and peritoneal metastasis in patients with the Cy-factor and histology in patients with the M-factor. Long-term survival can only be expected in patients with the Cy-factor who have neither macroscopic peritoneal metastasis nor lymph node metastasis or in patients with the M-factor who have a well-differentiated tumor.