The chemokine receptor CXCR4 is expressed in pancreatic intraepithelial neoplasia.

OBJECTIVE: The chemokine CXCL12, together with its specific receptor, CXCR4, have been shown to mediate invasiveness and metastatic behaviour in pancreatic cancer cells. The expression of CXC12/CXCR4 has not been previously examined in pancreatic intraepithelial neoplasias (PanIN), the accepted precursor lesions to pancreatic duct cancer. DESIGN: In this study we sought to characterise the expression of CXCL12 and CXCR4 during the progression of PanIN using both a murine model and human tissues. RESULTS: These studies reveal that both CXCL12 and CXCR4 are expressed in PanIN and that the frequency increases during PanIN progression (0% CXCR4 expression in normal mouse and human ducts vs 100% in mouse PanIN 3 and 77% in human PanIN 3). Next we demonstrate a dose-dependent increase in the proliferation of murine PanIN cells when exposed to CXCL12. Finally, we show that expression of CXCR4 in murine PanIN cells is partially dependent on mitogen-activated protein kinase (MAPK) signalling and that the effect of CXCL12 on PanIN proliferation can be abrogated by an MAPK inhibitor. CONCLUSIONS: Together these results demonstrate that CXCL12/CXCR4 expression begins in the pre-invasive stages of pancreatic neoplasia, and suggest that the presence of an autocrine loop that is at least partially regulated by MAPK signalling. Further studies that define the role of CXCR4 signalling in PanIN progression will determine if CXCR4 could serve as a novel target for chemoprevention and early stage therapy in pancreatic cancer.

A novel protein isoform of the RON tyrosine kinase receptor transforms human pancreatic duct epithelial cells.

The MST1R gene is overexpressed in pancreatic cancer producing elevated levels of the RON tyrosine kinase receptor protein. While mutations in MST1R are rare, alternative splice variants have been previously reported in epithelial cancers. We report the discovery of a novel RON isoform discovered in human pancreatic cancer. Partial splicing of exons 5 and 6 (P5P6) produces a RON isoform that lacks the first extracellular immunoglobulin-plexin-transcription domain. The splice variant is detected in 73% of xenografts derived from pancreatic adenocarcinoma patients and 71% of pancreatic cancer cell lines. Peptides specific to RON P5P6 detected in human pancreatic cancer specimens by mass spectrometry confirm translation of the protein isoform. The P5P6 isoform is found to be constitutively phosphorylated, present in the cytoplasm, and it traffics to the plasma membrane. Expression of P5P6 in immortalized human pancreatic duct epithelial (HPDE) cells activates downstream AKT, and in human pancreatic epithelial nestin-expressing cells, activates both the AKT and MAPK pathways. Inhibiting RON P5P6 in HPDE cells using a small molecule inhibitor BMS-777607 blocked constitutive activation and decreased AKT signaling. P5P6 transforms NIH3T3 cells and induces tumorigenicity in HPDE cells. Resultant HPDE-P5P6 tumors develop a dense stromal compartment similar to that seen in pancreatic cancer. In summary, we have identified a novel and constitutively active isoform of the RON tyrosine kinase receptor that has transforming activity and is expressed in human pancreatic cancer. These findings provide additional insight into the biology of the RON receptor in pancreatic cancer and are clinically relevant to the study of RON as a potential therapeutic target.

Preoperative and postoperative chemoradiation strategies in patients treated with pancreaticoduodenectomy for adenocarcinoma of the pancreas.

PURPOSE: The effects of preoperative versus postoperative fluorouracil (5-FU)-based chemotherapy and irradiation on treatment toxicity, duration of treatment, tumor recurrence, and survival were compared in patients who underwent potentially curative therapy for adenocarcinoma of the pancreatic head during a 5-year period. METHODS: From July 1990 to July 1995, 142 patients with localized adenocarcinoma of the pancreatic head deemed resectable on the basis of radiographic images were treated with curative intent using a multimodality approach involving either preoperative or postoperative chemoradiation. Patients with biopsy confirmation of adenocarcinoma and a low-density mass in the pancreatic head identified by computed tomography (CT) received preoperative chemoradiation. Patients without a mass on CT or in whom the preoperative biopsy was negative underwent pancreaticoduodenectomy with planned postoperative chemoradiation. Protocol-based preoperative chemoradiation consisted of external-beam irradiation at a dose of 50.4 Gy (standard fractionation; 1.8 Gy/d, 5 d/wk) or 30 Gy (rapid fractionation; 3 Gy/d, 5 d/wk) combined with continuous infusion 5-FU (300 mg/m2/d, 5 d/wk). Postoperative chemoradiation combined 50.4 Gy of external-beam irradiation (standard fractionation) with continuous-infusion 5-FU. RESULTS: No patient who received preoperative chemoradiation experienced a delay in surgery because of chemoradiation toxicity, but six of 25 eligible patients (24%) did not receive postoperative chemoradiation because of delayed recovery after pancreaticoduodenectomy. No significant differences in toxicities from chemoradiation were observed between groups. Patients treated with rapid-fractionation preoperative chemoradiation had a significantly (P < .01) shorter duration of treatment (median, 62.5 days) compared with patients who received postoperative chemoradiation (median, 98.5 days) or standard-fractionation preoperative chemoradiation (median, 91.0 days). At a median followup of 19 months, no significant differences in survival were observed between treatment groups. No patient who received preoperative chemoradiation and pancreaticoduodenectomy experienced a local recurrence; peritoneal (regional) recurrence occurred in 10% of these patients. Local or regional recurrence occurred in 21% of patients who received pancreaticoduodenectomy and postoperative chemoradiation. CONCLUSION: Delivery of preoperative and postoperative chemoradiation in patients who underwent potentially curative pancreaticoduodenectomy for adenocarcinoma of the pancreatic head resulted in similar treatment toxicity, patterns of tumor recurrence, and survival. Rapid-fractionation preoperative chemoradiation ensured the delivery of all components of therapy to all eligible patients with a significantly shorter duration of treatment than with standard-fractionation chemoradiation given either before or after pancreaticoduodenectomy. Prolonged recovery after pancreaticoduodenectomy prevents the delivery of postoperative adjuvant chemoradiation in up to one fourth of eligible patients.

Discrimination learning requiring different memory components in rats: age and neurochemical comparisons.

The performances of young (8-9 months) and aged (22-24 months) male ACI rats were compared in a T-maze requiring two discriminations, each of which placed different demands on memory processing. A spatial discrimination in the stem of the T-maze required long-term reference memory; a discrete-trial, alternation discrimination in the arms of the T-maze required working memory. Following acquisition training in one maze, rats were also trained in a second maze at a different location in the room. The correct response in the stem of this maze was opposite to that in the first maze. In two experiments with slightly different pretraining procedures, similar results demonstrated that aged rats made more errors in all phases of maze training than did their young counterparts. The results suggest that all components of memory processing were affected equivalently because the age-related impairment was not selectively greater in any component of the task. In a third experiment, aged rats were unimpaired in the ability to perform in a T-maze task involving a brightness discrimination with intramaze cues. This result suggests that the age-related impairment in the two-component T-maze task was restricted to the cognitive demands of the task. Neurochemical analyses were performed to determine whether regional neurotransmitter synthetic enzyme activities could be used to identify neurochemical systems associated with performance in these tasks and with any age-related impairments observed. Choline acetyltransferase and glutamic acid decarboxylase were assayed as markers for cholinergic and GABAergic systems, respectively, in the hippocampi and the following cortical regions: frontal, sensorimotor, auditory, cingulate, occipital, and pyriform-perirhinal. A slight (8%) but significant age-related decline was observed in the activity of glutamic acid decarboxylase but not of choline acetyltransferase. Although the correlation between maze performance and regional enzyme activities generally supported several previous observations, the only significant correlation to emerge was between working memory performance and glutamic acid decarboxylase activity in the cingulate cortex.

Laparoscopic staging for gastric cancer.

BACKGROUND: Laparoscopy has become an increasingly important diagnostic tool for the staging of intraabdominal malignancies. Some investigators have suggested laparoscopy to be of questionable value in the preoperative staging of gastric cancer because many patients may require palliative surgery despite laparoscopic findings. However, in other studies laparoscopy was found to be a more accurate staging technique and useful in avoiding unnecessary laparotomy when compared with abdominal sonography, liver scintigraphy, or early generation computed tomography (CT). In recent years marked improvements have been made in CT technology, and laparoscopy has not been compared with current generation CT. Therefore we sought to determine the usefulness of laparoscopy for staging gastric adenocarcinoma in the era of current generation CT scanning. METHODS: Staging laparoscopy was performed in 71 patients with potentially resectable gastric cancer as determined by physical examination and current generation CT. The results of laparoscopy were evaluated in the context of negative or equivocal CT findings. RESULTS: Laparoscopic staging was successful in 69 patients (97%). Laparoscopy identified distant metastatic disease in 16 (23%) patients judged to be eligible for potentially curative resection by current generation CT scanning. Only one of these patients required laparotomy for palliation. Combined CT and laparoscopic staging resulted in a 93% resectability rate for patients operated on with curative intent. CONCLUSIONS: We advocate staging laparoscopy as an important staging procedure for all patients with potentially resectable gastric cancer. The additional cost of laparoscopy should be more than offset by the decreased morbidity and expense of hospitalization for those patients who avoid an unnecessary laparotomy.

Significance of peritoneal cytology in patients with potentially resectable adenocarcinoma of the pancreatic head.

BACKGROUND: Recurrence in the peritoneum occurs in up to 50% of patients after a potentially curative pancreaticoduodenectomy. Previous authors have implicated preoperative fine-needle aspiration (FNA) as a cause of intraperitoneal tumor dissemination, although prior studies of peritoneal cytology findings have largely involved patients with locally advanced disease. METHODS: A consecutive series of patients referred to our institution between 1991 and 1993 with suspected or biopsy-proven adenocarcinoma of the pancreatic head was studied prospectively. All patients fulfilled criteria for resectability as assessed by computed tomography: no metastatic disease, no encasement of the superior mesenteric or hepatic arteries, and a patent superior mesenteric-portal venous confluence. Peritoneal washings were obtained at the time of staging laparoscopy and/or at subsequent laparotomy. Data regarding peritoneal cytology results, previous FNA, preoperative chemoradiation, eventual resection, pattern of disease recurrence, and survival were collected. RESULTS: A total of 80 peritoneal washings from 60 consecutive patients were prospectively examined. Forty-nine (82%) of 60 patients underwent FNA before peritoneal washings were obtained. A total of four patients (7%) had positive peritoneal cytology findings: three (6%) of 49 who underwent prior FNA and one (9%) of 11 with no prior FNA. Similarly, no differences in eventual peritoneal failure or short-term survival were observed for patients who underwent prior FNA compared with patients who did not. All four patients with positive peritoneal cytology findings had metastatic disease (liver, three; peritoneum, one) at a median of 4.8 months after diagnosis; three of the four died of disease at a median of 8 months. CONCLUSIONS: Positive peritoneal cytology findings are rare in patients with radiologically resectable adenocarcinoma of the pancreas. When found, positive peritoneal washings are an indicator of advanced disease characterized by unresectability, early metastasis, and short survival. Computed tomographic-guided FNA does not appear to increase the risk for positive peritoneal washings and represents a valid approach to the pretreatment diagnosis of patients with suspected pancreatic malignancy.

Surgical management of hereditary pancreatic cancer.

Pancreatic cancer continues to be a leading cause of cancer death in the United States. Seven genetic syndromes are now known to be associated with an increased incidence of pancreatic cancer. Other familial forms of pancreatic cancer exist although the genetic basis for this predisposition remains elusive. The similarities in the genetic and clinical manifestations of the sporadic and familial forms of pancreatic cancer suggest that pretreatment staging and management of patients with established pancreatic cancer should be similar. For carcinomas of the pancreatic head, pancreaticoduodenectomy should be performed according to current surgical practice, whereas the use of total pancreatectomy should be limited to cases in which margins are found to be positive or if the anatomy precludes a safe pancreaticojejunostomy. Total pancreatectomy may be considered in high-risk kindreds who strongly desire prophylactic surgery and in those with premalignant lesions. Identification of the precise genetic basis for inherited pancreatic cancer will someday make it possible to examine scientifically the effectiveness of specific management strategies.

Reoperative pancreaticoduodenectomy for periampullary carcinoma.

BACKGROUND: We have noted a continued increase in the number of patients referred to our institution for presumed or biopsy-proven periampullary carcinoma following an "exploratory" laparotomy during which tumor resection was not performed. Although previous work has demonstrated the safety of reoperative pancreaticoduodenectomy (PD), the need to avoid nontherapeutic laparotomy in these patients is obvious. In the current study, we sought to determine why PD was not performed at the initial operation. METHODS: Using the prospective pancreatic cancer database, we identified all patients who underwent reoperative PD at our institution between June 1990 and October 1995. Radiologic imaging prior to reoperation was standardized and based on thin-section, contrast-enhanced computed tomography (CT); helical CT was used in more recent cases. Pathologic data were obtained, and initial outside operative reports were reviewed to determine why a PD was not performed at the initial procedure. RESULTS: Twenty-nine patients underwent reoperative PD. Resection was not performed at the initial laparotomy because of the surgeon's assessment of local unresectability (17 patients), lack of a tissue diagnosis of malignancy (9), misdiagnoses (2), and error in intraoperative management (1). In the 17 patients deemed to have unresectable disease, successful reoperative PD required vascular resection in 10. All 10 of these patients had resection with negative microscopic margins of excision. Of the 9 patients who did not have resection owing to diagnostic uncertainty, all 9 had undergone multiple intraoperative biopsies interpreted as negative for malignancy; 6 of 9 had carcinoma confirmed on permanent-section analysis of the biopsy specimens. Four patients suffered major complications from intraoperative large-needle biopsy. CONCLUSIONS: Detailed preoperative imaging and a clearly defined operative plan would have allowed successful resection at the initial operation in 27 of 29 patients who underwent reoperative PD. Avoidable patient morbidity and the cost of unnecessary surgery argue strongly against "exploratory" surgery in patients with presumed periampullary neoplasms.

Adjuvant/neoadjuvant chemoradiation for gastric and pancreatic cancer.

Both gastric and pancreatic cancer remain leading causes of cancer death in the United States and worldwide. While surgical resection continues to be required for long-term cure of both these neoplasms, 5-year survival rates remain poor following surgery alone. For both gastric and pancreatic cancers, studies examining patterns of recurrence following apparently curative resection repeatedly demonstrate high rates of locoregional relapse. In this setting, the addition of chemoradiation delivered either before or following surgery represents a logical strategy to improve local tumor control and possibly improve survival. Data suggest that 5-fluorouracil-based chemoradiation, when given at sufficient doses, can effectively palliate patients with unresectable gastric cancer. Whether this approach improves response and survival in patients with resectable gastric cancer remains investigational. Results of ongoing and recently completed trials will provide further information on the utility of 5-fluorouracil-based regimens, as well as the use of other radiation sensitizers, in the adjuvant setting. In patients with resectable pancreatic cancer, the primary goal should be to perform a margin-negative pancreaticoduodenectomy. The use of neoadjuvant chemoradiation may increase the likelihood of achieving this goal, and this approach is being investigated.

Clinical and preclinical trials of isolated liver perfusion for advanced liver tumors: primary liver tumors.

Preclinical serum and tissue pharmacology studies have played a key role in the development and testing of this novel system designed to treat liver tumors. Pharmacologic evaluation confirmed that the CVHI-CF system significantly limited systemic serum and tissue exposure to chemotherapy drugs given by HAI. By reducing systemic drug exposure and, thus, limiting systemic toxicity, higher doses of antitumor agents can be administered to enhance intratumoral drug levels and increase tumor cell kill. The CVHI-CF system will likely prove increasingly valuable as more active chemotherapeutic agents are developed to treat hepatic malignancies.

Oncogenic Ras/Src cooperativity in pancreatic neoplasia.

Pancreas cancer is one of the most lethal malignancies and is characterized by activating mutations of Kras, present in 95% of patients. More than 60% of pancreatic cancers also display increased c-Src activity, which is associated with poor prognosis. Although loss of tumor suppressor function (for example, p16, p53, Smad4) combined with oncogenic Kras signaling has been shown to accelerate pancreatic duct carcinogenesis, it is unclear whether elevated Src activity contributes to Kras-dependent tumorigenesis or is simply a biomarker of disease progression. Here, we demonstrate that in the context of oncogenic Kras, activation of c-Src through deletion of C-terminal Src kinase (CSK) results in the development of invasive pancreatic ductal adenocarcinoma (PDA) by 5-8 weeks. In contrast, deletion of CSK alone fails to induce neoplasia, while oncogenic Kras expression yields PDA at low frequency after a latency of 12 months. Analysis of cell lines derived from Ras/Src-induced PDA's indicates that oncogenic Ras/Src cooperativity may lead to genomic instability, yet Ras/Src-driven tumor cells remain dependent on Src signaling and as such, Src inhibition suppresses growth of Ras/Src-driven tumors. These findings demonstrate that oncogenic Ras/Src cooperate to accelerate PDA onset and support further studies of Src-directed therapies in pancreatic cancer.

The significance and clinical factors associated with a subcentimeter resection of colorectal liver metastases.

BACKGROUND: Prognosis after resection of colorectal liver metastases is influenced by various factors. A positive margin of resection (MOR) has been shown to adversely influence prognosis. Although a 1-cm MOR has been accepted as adequate, the data to support this guideline are sparse. METHODS: Our hepatobiliary database was queried for patients who underwent liver resection for colorectal metastases between January 1992 and July 2003. All patients were divided into three groups: MOR <.5 cm (group A), .5 to 1 cm (group B), and >1 cm (group C). Operative reports from each hepatic resection were analyzed to determine local factors that may have contributed to a subcentimeter MOR. RESULTS: A total of 112 patients (67 men and 45 women) underwent liver resection for colorectal metastases with negative margins. Fifty-three patients were in group A, 26 patients were in group B, and 33 patients were in group C. Group C demonstrated decreased local recurrence (LR; P = .003), distant recurrence (DR; P = .008), and disease-free recurrence (P = .002). A significant difference in the overall time to LR (P = .003), time to DR (P = .003), and disease-free survival (P = .002) was also demonstrated. Factors associated with a subcentimeter MOR included nonanatomical resection (P = .043), proximity to a major vessel (P = .003), and central location (P = .002). CONCLUSIONS: A <1-cm resection for colorectal liver metastases is associated with increased LR and DR, as well as decreased disease-free survival. When a nonanatomical resection is performed, a MOR >1 cm should be attempted, because an adequate margin is often underestimated. Considerations should be made for extended resections when tumors are centrally located or near major vessels.

Laparotomy in patients infected with human immunodeficiency virus: indications and outcome.

Four distinct disease processes account for the majority of surgically correctable intra-abdominal pathologies associated with human immunodeficiency virus (HIV) infection: cytomegalovirus infection, Kaposi's sarcoma, non-Hodgkin's lymphoma and mycobacterial infection. Affected patients may also develop acute cholecystitis and appendicitis with significant frequency. Thorough investigation, when possible, will obviate the need for laparotomy in most HIV-infected patients with abdominal symptoms and signs. In those who require surgical intervention, the outcome varies greatly according to the nature of the diagnosis.

Pancreatic cancer: can we screen? How should we stage?

Pancreatic cancer remains a deadly disease, with few patients surviving 5 years following diagnosis. Surgical resection remains the only treatment associated with the potential for cure; however, most patients have locally advanced or metastatic disease at presentation and thus are not surgical candidates. Advances in imaging technologies, biochemistry, and molecular genetics have raised hopes of improving the outcome for patients with pancreatic cancer through earlier and more accurate diagnosis. As our knowledge of the genetics of pancreatic cancer has increased, the possibility of screening to identify patients at risk to develop the disease also holds promise. This review focuses on the utility of current modalities to screen for pancreatic cancer as well as the most accurate and expedient methods to stage the disease.

Adjuvant therapy for resectable gastric adenocarcinoma: preoperative and postoperative chemotherapy trials.

Survival rates for patients undergoing resection of gastric adenocarcinoma remain poor. Even following successful removal of all gross disease, high rates of local-regional and systemic recurrence are observed. During the past twenty-five years, multiple trials have been undertaken to evaluate the possible benefit of either preoperative or postoperative adjuvant chemotherapy in this disease. This report reviews the rationale, design, and outcome of these trials, and further updates the status of preoperative chemotherapy protocols currently employed at the M.D. Anderson Cancer Center.

Phosphorylation of the tumor suppressor adenomatous polyposis coli (APC) by the cyclin-dependent kinase p34.

Mutations in the tumor suppressor gene APC invariably lead to the development of colorectal cancer. The vast majority of these mutations are nonsense or frameshifts resulting in nonfunctional, truncated APC protein products. Eleven cyclin-dependent kinase (CDK) consensus phosphorylation sites have been identified in the frequently deleted carboxyl-terminal region of APC; loss of these phosphorylation sites by mutation could therefore compromise the ability of APC to inhibit cell growth. This report demonstrates that immunoprecipitates of full-length, but not truncated, APC protein include a mitosis-specific kinase activity in vivo. Biochemical and Western analysis of these immunoprecipitates confirms the presence of the CDK p34(cdc2). We also show that APC is a substrate for recombinant human p34(cdc2)-cyclin B1. Modification of APC by p34(cdc2) implicates phosphorylation as a mechanism for regulating APC function via a link to the cell cycle.

Mutation of phosphoserine 389 affects p53 function in vivo.

To study the importance of phosphorylation for p53 transactivation function, we generated mutations at each of its known phosphorylated serine amino acids. Mutations of murine p53 serine residues individually to either alanine or glutamic acid at positions 7, 9, 12, 18, 37, 312, and 389 resulted in equivalent levels of transcriptional activation in standard transient transfection experiments. However, when p53 transcriptional activity was measured in cells that attain G1 arrest upon contact inhibition, wild-type p53 was inactive, and only alteration at serine 389 to glutamic acid resulted in a functional p53 protein. This Ser --> Glu mutant also has an increased ability to bind DNA. Elimination of the phosphorylation site by substitution of an alanine amino acid resulted in loss of transcriptional activity. We also demonstrated that specific phosphorylation of p53 at serine 389 is induced by cyclin E overexpression in high-density cells. Our data establish for the first time that phosphorylation of p53 at serine 389 is important in activating its function in vivo.

Response to neoadjuvant chemotherapy best predicts survival after curative resection of gastric cancer.

OBJECTIVE: In Western populations, long-term survival rates after curative resection of gastric cancer remain extremely poor. The lack of effective adjuvant therapy has prompted the evaluation of neoadjuvant approaches. Since 1988, we have conducted three separate phase II trials using neoadjuvant chemotherapy to treat patients with potentially resectable gastric cancer. The present study was conducted to evaluate whether response to neoadjuvant chemotherapy is predictive of survival in patients with resectable gastric cancer. METHODS: Eighty-three patients with pathologically confirmed gastric adenocarcinoma were treated with neoadjuvant chemotherapy before planned surgical resection. Response was assessed by upper gastrointestinal series, endoscopy, computed tomography scan, and pathologic examination. RESULTS: For the three phase II trials, clinical response rates ranged from 24% to 38%. Three patients (4%) had a complete pathologic response. Sixty-one patients (73%) underwent a curative resection. Median follow-up was 26 months. Univariate analysis revealed T stage, number of positive nodes, and response to chemotherapy to be significant predictors of overall survival. However, on multivariate analysis, response to chemotherapy was found to be the only independent prognostic factor. CONCLUSIONS: Response to neoadjuvant chemotherapy is the single most important predictor of overall survival after neoadjuvant chemotherapy for gastric cancer. These findings support further evaluation of neoadjuvant approaches in the treatment of this disease.

Numerous colonic adenomas in an individual with Bloom's syndrome.

Bloom's syndrome (BS) is a rare recessive disorder caused by germline mutation of the BLM gene. Individuals with BS manifest growth retardation, immunodeficiency, and a predisposition to cancer. In this report, we describe an individual with BS and multiple colonic adenomas reminiscent of familial adenomatous polyposis coli (FAP). Molecular studies revealed APC mutations in 4 of 6 adenomas, including 2 adenomas with the identical APC mutation and microsatellite instability in 1 of 6 adenomas. These results demonstrate similar pathways to colorectal neoplasia in BS as in the normal population and suggest that individuals with BS may be particularly susceptible to colorectal neoplasia.