A systematic review and meta-analysis of germline BRCA mutations in pancreatic cancer patients identifies global and racial disparities in access to genetic testing

BACKGROUND

Germline BRCA1 and BRCA2 mutations (gBRCAm) can inform pancreatic cancer (PC) risk and treatment but most of the available information is derived from white patients. The ethnic and geographic variability of gBRCAm prevalence and of germline BRCA (gBRCA) testing uptake in PC globally is largely unknown.

MATERIALS AND METHODS

We carried out a systematic review and prevalence meta-analysis of gBRCA testing and gBRCAm prevalence in PC patients stratified by ethnicity. The main outcome was the distribution of gBRCA testing uptake across diverse populations worldwide. Secondary outcomes included: geographic distribution of gBRCA testing uptake, temporal analysis of gBRCA testing uptake in ethnic groups, and pooled proportion of gBRCAm stratified by ethnicity. The study is listed under PROSPERO registration number #CRD42022311769.

RESULTS

A total of 51 studies with 16 621 patients were included. Twelve of the studies (23.5%) enrolled white patients only, 10 Asians only (19.6%), and 29 (56.9%) included mixed populations. The pooled prevalence of white, Asian, African American, and Hispanic patients tested per study was 88.7%, 34.8%, 3.6%, and 5.2%, respectively. The majority of included studies were from high-income countries (HICs) (64; 91.2%). Temporal analysis showed a significant increase only in white and Asians patients tested from 2000 to present (P < 0.001). The pooled prevalence of gBRCAm was: 3.3% in white, 1.7% in Asian, and negligible (<0.3%) in African American and Hispanic patients.

CONCLUSIONS

Data on gBRCA testing and gBRCAm in PC derive mostly from white patients and from HICs. This limits the interpretation of gBRCAm for treating PC across diverse populations and implies substantial global and racial disparities in access to BRCA testing in PC.

Reshaping preoperative treatment of pancreatic cancer in the era of precision medicine

This review summarises the recent evidence on preoperative therapeutic strategies in pancreatic cancer and discusses the rationale for an imminent need for a personalised therapeutic approach in non-metastatic disease. The molecular diversity of pancreatic cancer and its influence on prognosis and treatment response, combined with the failure of 'all-comer' treatments to significantly impact on patient outcomes, requires a paradigm shift towards a genomic-driven approach. This is particularly important in the preoperative, potentially curable setting, where a personalised treatment allocation has the substantial potential to reduce pancreatic cancer mortality.

Different shades of pancreatic ductal adenocarcinoma, different paths towards precision therapeutic applications

BACKGROUND

Different histological and molecular subtypes of pancreatic ductal adenocarcinoma (PDAC), with different molecular composition and survival statistics, have recently been recognised.

MATERIALS AND METHODS

This review describes the currently available studies regarding molecular and histological subtypes in PDAC. Studies from major cohorts such as International Cancer Genome Consortium as well as smaller cohorts are reviewed. We discuss where the described subtypes overlap, where the discrepancies are and which paths forward could be taken regarding diagnosis, ontogeny and therapy.

RESULTS

Four molecular subtypes with strong overlap among the different studies can be found, next to a list of mixed findings. Two of the four subtypes (epithelial classical and mesenchymal basal-like) were represented in every study and were often discriminated in other solid tumours as well. These two subtypes differ substantially in prognosis. One biomarker has been discovered, only discriminating these two subtypes, and insights into subtype-specific therapeutic vulnerabilities are scarce.

CONCLUSION

Subtypes can be reproducibly detected in cohorts of PDAC patients and two of them directly relate with prognosis. A consensus on the subtypes is warranted. Further discovery and validation studies are needed to identify strong biomarkers, to comprehend subtype ontogeny and to define strategies for precision medicine.

Defining the molecular pathology of pancreatic body and tail adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) remains a dismal disease, with very little improvement in survival over the past 50 years. Recent large-scale genomic studies have improved understanding of the genomic and transcriptomic landscape of the disease, yet very little is known about molecular heterogeneity according to tumour location in the pancreas; body and tail PDACs especially tend to have a significantly worse prognosis. The aim was to investigate the molecular differences between PDAC of the head and those of the body and tail of the pancreas.

METHODS

Detailed correlative analysis of clinicopathological variables, including tumour location, genomic and transcriptomic data, was performed using the Australian Pancreatic Cancer Genome Initiative (APGI) cohort, part of the International Cancer Genome Consortium study.

RESULTS

Clinicopathological data were available for 518 patients recruited to the APGI, of whom 421 underwent genomic analyses; 179 of these patients underwent whole-genome and 96 RNA sequencing. Patients with tumours of the body and tail had significantly worse survival than those with pancreatic head tumours (12·1 versus 22·0 months; P = 0·001). Location in the body and tail was associated with the squamous subtype of PDAC. Body and tail PDACs enriched for gene programmes involved in tumour invasion and epithelial-to-mesenchymal transition, as well as features of poor antitumour immune response. Whether this is due to a molecular predisposition from the outset, or reflects a later time point on the tumour molecular clock, requires further investigation using well designed prospective studies in pancreatic cancer.

CONCLUSION

PDACs of the body and tail demonstrate aggressive tumour biology that may explain worse clinical outcomes.

SerpinB2 regulates stromal remodelling and local invasion in pancreatic cancer

Pancreatic cancer has a devastating prognosis, with an overall 5-year survival rate of ~8%, restricted treatment options and characteristic molecular heterogeneity. SerpinB2 expression, particularly in the stromal compartment, is associated with reduced metastasis and prolonged survival in pancreatic ductal adenocarcinoma (PDAC) and our genomic analysis revealed that SERPINB2 is frequently deleted in PDAC. We show that SerpinB2 is required by stromal cells for normal collagen remodelling in vitro, regulating fibroblast interaction and engagement with collagen in the contracting matrix. In a pancreatic cancer allograft model, co-injection of PDAC cancer cells and SerpinB2-/- mouse embryonic fibroblasts (MEFs) resulted in increased tumour growth, aberrant remodelling of the extracellular matrix (ECM) and increased local invasion from the primary tumour. These tumours also displayed elevated proteolytic activity of the primary biochemical target of SerpinB2-urokinase plasminogen activator (uPA). In a large cohort of patients with resected PDAC, we show that increasing uPA mRNA expression was significantly associated with poorer survival following pancreatectomy. This study establishes a novel role for SerpinB2 in the stromal compartment in PDAC invasion through regulation of stromal remodelling and highlights the SerpinB2/uPA axis for further investigation as a potential therapeutic target in pancreatic cancer.

Delineating the Role of βIV-Tubulins in Pancreatic Cancer: βIVb-Tubulin Inhibition Sensitizes Pancreatic Cancer Cells to Vinca Alkaloids

Pancreatic cancer (PC) is a lethal disease which is characterized by chemoresistance. Components of the cell cytoskeleton are therapeutic targets in cancer. βIV-tubulin is one such component that has two isotypes-βIVa and βIVb. βIVa and βIVb isotypes only differ in two amino acids at their C-terminus. Studies have implicated βIVa-tubulin or βIVb-tubulin expression with chemoresistance in prostate, breast, ovarian and lung cancer. However, no studies have examined the role of βIV-tubulin in PC or attempted to identify isotype specific roles in regulating cancer cell growth and chemosensitivity. We aimed to determine the role of βIVa- or βIVb-tubulin on PC growth and chemosensitivity. PC cells (MiaPaCa-2, HPAF-II, AsPC1) were treated with siRNA (control, βIVa-tubulin or βIVb-tubulin). The ability of PC cells to form colonies in the presence or absence of chemotherapy was measured by clonogenic assays. Inhibition of βIVa-tubulin in PC cells had no effect chemosensitivity. In contrast, inhibition of βIVb-tubulin in PC cells sensitized to vinca alkaloids (Vincristine, Vinorelbine and Vinblastine), which was accompanied by increased apoptosis and enhanced cell cycle arrest. We show for the first time that βIVb-tubulin, but not βIVa-tubulin, plays a role in regulating vinca alkaloid chemosensitivity in PC cells. The results from this study suggest βIVb-tubulin may be a novel therapeutic target and predictor of vinca alkaloid sensitivity for PC and warrants further investigation.

Pancreatic cancer genomics: where can the science take us?

The incidence of pancreatic ductal adenocarcinoma (PDAC) is steadily increasing and the annual death-to-incidence ratio approaches one. This is a figure that has not changed for several decades. Surgery remains the only chance of cure; however, only less than 20% of patients are amenable to operative resection. Despite successful surgical resection, the majority of the patients still succumb to recurrent metastatic disease. Therefore, there is an urgent need to develop novel therapeutic strategies and to better select patients for current therapies. In this review, we will discuss current management by highlighting the landmark clinical trials that have shaped current care. We will then discuss the challenges of therapeutic development using the current randomized-controlled trial paradigm when confronted with the molecular heterogeneity of PDAC. Finally, we will discuss strategies that may help to shape the management of PDAC in the near future.

Histone deacetylase 5 blocks neuroblastoma cell differentiation by interacting with N-Myc

The N-Myc oncoprotein induces neuroblastoma, which arises from undifferentiated neuroblasts in the sympathetic nervous system, by modulating gene and protein expression and consequently causing cell differentiation block and cell proliferation. The class IIa histone deacetylase 5 (HDAC5) represses gene transcription, and blocks myoblast, osteoblast and leukemia cell differentiation. Here we showed that N-Myc upregulated HDAC5 expression in neuroblastoma cells. Conversely, HDAC5 repressed the ubiquitin-protein ligase NEDD4 gene expression, increased Aurora A gene expression and consequently upregulated N-Myc protein expression. Genome-wide gene expression analysis and protein co-immunoprecipitation assays revealed that HDAC5 and N-Myc repressed the expression of a common subset of genes by forming a protein complex, whereas HDAC5 and the class III HDAC SIRT2 independently repressed the expression of another common subset of genes without forming a protein complex. Moreover, HDAC5 blocked differentiation and induced proliferation in neuroblastoma cells. Taken together, our data identify HDAC5 as a novel co-factor in N-Myc oncogenesis, and provide the evidence for the potential application of HDAC5 inhibitors in the therapy of N-Myc-induced neuroblastoma and potentially other c-Myc-induced malignancies.

Adjuvant chemotherapy in elderly patients with pancreatic cancer

BACKGROUND

Adjuvant chemotherapy improves survival for patients with resected pancreatic cancer. Elderly patients are under-represented in Phase III clinical trials, and as a consequence the efficacy of adjuvant therapy in older patients with pancreatic cancer is not clear. We aimed to assess the use and efficacy of adjuvant chemotherapy in older patients with pancreatic cancer.

METHODS

We assessed a community cohort of 439 patients with a diagnosis of pancreatic ductal adenocarcinoma who underwent operative resection in centres associated with the Australian Pancreatic Cancer Genome Initiative.

RESULTS

The median age of the cohort was 67 years. Overall only 47% of all patients received adjuvant therapy. Patients who received adjuvant chemotherapy were predominantly younger, had later stage disease, more lymph node involvement and more evidence of perineural invasion than the group that did not receive adjuvant treatment. Overall, adjuvant chemotherapy was associated with prolonged survival (median 22.1 vs 15.8 months; P<0.0001). Older patients (aged ≥70) were less likely to receive adjuvant chemotherapy (51.5% vs 29.8%; P<0.0001). Older patients had a particularly poor outcome when adjuvant therapy was not delivered (median survival=13.1 months; HR 1.89, 95% CI: 1.27-2.78, P=0.002).

CONCLUSION

Patients aged ≥70 are less likely to receive adjuvant therapy although it is associated with improved outcome. Increased use of adjuvant therapy in older individuals is encouraged as they constitute a large proportion of patients with pancreatic cancer.

The prognostic and predictive value of serum CA19.9 in pancreatic cancer

Background

Current staging methods for pancreatic cancer (PC) are inadequate, and biomarkers to aid clinical decision making are lacking. Despite the availability of the serum marker carbohydrate antigen 19.9 (CA19.9) for over two decades, its precise role in the management of PC is yet to be defined, and as a consequence, it is not widely used.

Methods

We assessed the relationship between perioperative serum CA19.9 levels, survival and adjuvant chemotherapeutic responsiveness in a cohort of 260 patients who underwent operative resection for PC.

Results

By specifically assessing the subgroup of patients with detectable CA19.9, we identified potential utility at key clinical decision points. Low postoperative CA19.9 at 3 months (median survival 25.6 vs 14.8 months, P = 0.0052) and before adjuvant chemotherapy were independent prognostic factors. Patients with postoperative CA 19.9 levels >90 U/ml did not benefit from adjuvant chemotherapy (P = 0.7194) compared with those with a CA19.9 of ≤90 U/ml (median 26.0 vs 16.7 months, P = 0.0108). Normalization of CA19.9 within 6 months of resection was also an independent favorable prognostic factor (median 29.9 vs 14.8 months, P = 0.0004) and normal perioperative CA19.9 levels identified a good prognostic group, which was associated with a 5-year survival of 42%.

Conclusions

Perioperative serum CA19.9 measurements are informative in patients with detectable CA19.9 (defined by serum levels of >5 U/ml) and have potential clinical utility in predicting outcome and response to adjuvant chemotherapy. Future clinical trials should prioritize incorporation of CA19.9 measurement at key decision points to prospectively validate these findings and facilitate implementation.

A molecular prognostic nomogram for resectable pancreatic cancer

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Background: Defining clinically and biologically relevant phenotypes in other cancers has led to substantial improvements in the overall outcomes, but as yet none have been defined for pancreatic cancer (PC). About 80% of patients with pancreatic cancer succumb to the disease despite curative resection, many of whom within 6 months of surgery. There is a clear need to better define the biology and clinical behaviour of PC. This study aimed to evaluate the potential clinical utility of biologically relevant molecules as prognostic factors in resected PC.

Methods: We assessed the relationship of aberrant S100A4 calcium-binding protein expression with survival in a cohort of 372 patients who underwent surgical resection for PC and derived a nomogram using clinicopathologic variables and aberrant expression of S100A4 and S100A2.

Results: High S100A4 expression was an independent poor prognostic factor in both the training (n = 76; HR = 5.00, 95% CI = 2.29 – 10.9; p < 0.0001) and validation sets (n = 296; HR = 1.78, 95% CI = 1.29 – 2.46; p = 0.0004). Incorporating previously published data on S100A2, demonstrated that high expression of S100A4 was still an independent prognostic factor. Aberrant expression of these proteins stratified the cohort into three distinct prognostic groups. A preoperative nomogram using only variables that could be measured preoperatively (tumor size and molecular biomarkers), predicted survival better than nomograms derived from using clinicopathologic variables, which are only determined after examination of the resected specimen.

Conclusions: Aberrant expression of S100A4 and S100A2 stratifies PC into distinct prognostic groups and improves the accuracy of prognostic nomograms using variables that can be determined preoperatively. The development and application of such nomograms in routine clinical practice has the potential to improve patient selection and as a consequence overall outcomes for PC.

No significant financial relationships to disclose.

Molecular pathologic phenotypes and outcome in adenocarcinoma of the ampulla of Vater

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Background: Individuals with adenocarcinoma of the ampulla of Vater demonstrate a broad range of outcomes, as they may arise from any of the three epithelia that converge at that location. This variation in outcomes poses specific challenges in clinical decision making concerning the aggressiveness of treatment, and the appropriateness and type of adjuvant therapy.

Methods: We assessed the relationship between molecular pathologic phenotypes defined using a combination of histopathology and protein expression (CDX2 [caudal-type homeodomain transcription factor 2] and MUC1), and outcome in 72 patients who underwent operative resection for adenocarcinoma of the ampulla of Vater.

Results: Patients with a pancreaticobiliary phenotype (CDX2 negative, MUC1 positive) compared to an intestinal phenotype carcinoma segregated into an independently poor prognostic group (HR = 3.40, 95% CI: 1.71 – 6.76, p = 0.0005). Stratification using lymph node (LN) status (the only other independent poor prognostic factor) (HR = 3.19, 95% CI: 1.54 – 6.58, p = 0.0017) defined three clinically relevant phenotypes: 1) those with a non-pancreaticobiliary (intestinal) phenotype without LN metastases who had an excellent outcome (5-year survival 88.4%, median survival 172.8 months); 2) those that had a pancreaticobiliary phenotype and lymph node metastases that had a poor outcome (5-year survival 20.0%, median survival 7.4 months); and 3) the remainder (intestinal/LN positive or pancreaticobiliary/LN negative) who had an intermediate outcome (5-year survival 46.9%, median survival 57.0 months).

Conclusions: A combination of histopathologic and molecular criteria identified three distinct clinically relevant phenotypes of adenocarcinoma of the ampulla of Vater that have significantly different outcomes. This distinction, which requires validation, may be used to refine current therapeutic strategies by guiding aggressiveness of surgery and selection for adjuvant therapy, which would improve overall outcomes.

No significant financial relationships to disclose.

Superior mesenteric artery syndrome: diagnosis and treatment strategies

INTRODUCTION

Superior mesenteric artery (SMA) syndrome is an unusual cause of vomiting and weight loss resulting from the compression of the third part of the duodenum by the SMA. Various medical and psychiatric conditions may result in the initial rapid weight loss which causes narrowing of the aortomesenteric angle. The vomiting and obstructive syndrome is then self-perpetuated regardless of the initiating factors. The young age and nonspecific symptoms often lead to a delay in diagnosis.

DISCUSSION

A series of eight cases is presented reviewing the presentation, investigations, surgical treatment by division of duodenum and duodenojejunostomy, and outcomes.

CONCLUSION

SMA syndrome is a well-described entity which must be considered as a cause of vomiting associated with significant weight loss in young adults. Surgical treatment should be allied with psychological assessment to treat any underlying psychosocial abnormality.

Expression of LMO4 and outcome in pancreatic ductal adenocarcinoma

Identification of a biomarker of prognosis and response to therapy that can be assessed preoperatively would significantly improve overall outcomes for patients with pancreatic cancer. In this study, patients whose tumours exhibited high LMO4 expression had a significant survival advantage following operative resection, whereas the survival of those patients whose tumours had low or no LMO4 expression was not significantly different when resection was compared with operative biopsy alone.

Use of the novel biomarker (HOXB2) to predict response to pancreatectomy for pancreatic cancer

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Background: Pancreatectomy is the only therapeutic intervention that offers the chance of long term survival for patients with pancreatic cancer, however, only 10% of patients who undergo pancreatectomy survive > 3 years with prognostic factors only determined after pathological examination of the resected specimen. Identification of a biomarker of response to surgical resection that can be determined preoperatively offers the potential to significantly improve survival and quality of life for patients with PC by improving patient selection for pancreatectomy. Methods: We examined the aberrant expression of over 20 genes identified using transcript profiling or known to be important in carcinogenesis using immunohistochemistry and in-situ hybridisation in a cohort of 124 patients with pancreatic cancer to identify potential biomarkers of prognosis and response to operative resection. Results: Aberrant expression of p53, p21WAF1/CIP1, p27KIP1, p16INK4A, cyclin D1, cyclin E, DPC4/Smad4, EGFR, beta-catenin, sfrp4, LMO4, HOXB2, S100P, S100A6, S100A2, RAI3 and CRBP1 were identified in a significant proportion of PC. Multivariate analysis of clinicopathological variables (tumor size, differentiation, subtype, lymph node metastases, perineural invasion and vascular space invasion), treatment parameters (margin involvement, adjuvant therapy, resection type), and aberrant expression of the above candidate biomarkers identified that HOXB2 expression and resection margin involvement by tumor were the only 2 independent prognostic factors. Patients who had absent HOXB2 expression and had clear margins after pancreaticoduodenectomy (48%) had an actual survival of 40% at 3 years and 21% at 5 years, compared to those with HOXB2 expression and/or positive surgical margins who had all died by 28 months. Conclusion: HOXB2 expression may represent a surrogate marker of advanced disease, can potentially be assessed preoperatively using FNAB, and is currently the best predictor of outcome and response to operative resection to be reported. Preoperative assessment of HOXB2 expression has potential clinical utility in predicting response to operative resection for PC to allow better selection of patients for operative intervention.

No significant financial relationships to disclose.

Endoplasmic reticulum stress contributes to beta cell apoptosis in type 2 diabetes

AIMS/HYPOTHESIS

Increased lipid supply causes beta cell death, which may contribute to reduced beta cell mass in type 2 diabetes. We investigated whether endoplasmic reticulum (ER) stress is necessary for lipid-induced apoptosis in beta cells and also whether ER stress is present in islets of an animal model of diabetes and of humans with type 2 diabetes.

METHODS

Expression of genes involved in ER stress was evaluated in insulin-secreting MIN6 cells exposed to elevated lipids, in islets isolated from db/db mice and in pancreas sections of humans with type 2 diabetes. Overproduction of the ER chaperone heat shock 70 kDa protein 5 (HSPA5, previously known as immunoglobulin heavy chain binding protein [BIP]) was performed to assess whether attenuation of ER stress affected lipid-induced apoptosis.

RESULTS

We demonstrated that the pro-apoptotic fatty acid palmitate triggers a comprehensive ER stress response in MIN6 cells, which was virtually absent using non-apoptotic fatty acid oleate. Time-dependent increases in mRNA levels for activating transcription factor 4 (Atf4), DNA-damage inducible transcript 3 (Ddit3, previously known as C/EBP homologous protein [Chop]) and DnaJ homologue (HSP40) C3 (Dnajc3, previously known as p58) correlated with increased apoptosis in palmitate- but not in oleate-treated MIN6 cells. Attenuation of ER stress by overproduction of HSPA5 in MIN6 cells significantly protected against lipid-induced apoptosis. In islets of db/db mice, a variety of marker genes of ER stress were also upregulated. Increased processing (activation) of X-box binding protein 1 (Xbp1) mRNA was also observed, confirming the existence of ER stress. Finally, we observed increased islet protein production of HSPA5, DDIT3, DNAJC3 and BCL2-associated X protein in human pancreas sections of type 2 diabetes subjects.

CONCLUSIONS/INTERPRETATION

Our results provide evidence that ER stress occurs in type 2 diabetes and is required for aspects of the underlying beta cell failure.

Skills acquired on virtual reality laparoscopic simulators transfer into the operating room in a blinded, randomised, controlled trial

Virtual reality surgical simulators have proven value in the acquisition and assessment of laparoscopic skills. In this study, we investigated skill transfer from a virtual reality laparoscopic simulator into the operating room, using a blinded, randomised, controlled trial design. Surgical trainees using the LapSim System performed significantly better at their first real-world attempt at a laparoscopic task than their colleagues who had not received similar training, as measured independently by a number of expert surgical observers using four criteria.

Aberrant p16(INK4A) and DPC4/Smad4 expression in intraductal papillary mucinous tumours of the pancreas is associated with invasive ductal adenocarcinoma

BACKGROUND AND AIMS

Intraductal papillary mucinous tumours (IPMT) of the pancreas constitute a unique pathological entity with an overall incidence of associated invasive malignancy of 20%. The malignant potential of an individual IPMT cannot be accurately predicted. Preoperative estimation of the risk of associated invasive malignancy with IPMT would be of significant clinical benefit. As aberrations in cell cycle regulatory genes are associated with the progression of precursor pancreatic ductal lesions to invasive adenocarcinoma, we examined expression of key cell cycle regulatory genes in the cyclin D1/retinoblastoma pathway and the transforming growth factor beta/Smad4 signalling pathway in a cohort of patients with surgically resected IPMT.

METHODS

Sections of formalin fixed paraffin embedded pancreatic tissue from a cohort of 18 patients with IPMT were examined using immunohistochemistry for protein expression of cell cycle regulatory genes p16(INK4A), p21(CIP1), p27(KIP1), cyclin D1, pRb, and p53, as well as the cell signalling molecule Smad4. A comparison of expression levels was made between adenoma/borderline IPMT (10 patients) and intraductal papillary mucinous carcinoma (IPMC) (eight patients, four of whom harboured invasive carcinoma). Statistical analysis was performed using the chi(2) and Fisher's exact tests.

RESULTS

Aberrant expression of the proteins examined increased in frequency from adenoma/borderline IPMT to IPMC. Specifically, there was a significantly greater incidence of loss of p16(INK4A) expression in IPMC: 8/8 lesions (100%) compared with 1/10 (10%) adenoma/borderline IPMT (p<0.001). Similarly, loss of Smad4 expression was associated with IPMC: 3/8 (38%) versus adenoma/borderline IPMT 0/10 (p<0.03). Loss of Smad4 expression within the IPMT was the best marker for the presence of invasive carcinoma (p<0.001).

CONCLUSIONS

These data indicate that loss of p16(INK4A) and Smad4 expression occur more frequently in IPMC alone, or with associated invasive carcinoma, compared with adenoma/borderline IPMT. Aberrant protein expression of these cell cycle regulatory genes in IPMT and pancreatic intraepithelial neoplasia in the current model of pancreatic cancer progression suggest similarities in their development and may also represent the subsequent risk of invasive carcinoma.

Overexpression of p21(WAF1/CIP1) is an early event in the development of pancreatic intraepithelial neoplasia

Pancreatic cancer (PC) is thought to develop through a series of duct lesions termed pancreatic intraepithelial neoplasia (PanIN). Characterization of the molecular pathology of these lesions may lead to additional understanding of pancreatic ductal carcinogenesis. We examined the protein expression of four functionally related genes, p21(WAF1/CIP1) (CDKN1A), p53, cyclin D1 (CCND1), and DPC4/Smad4 (MADH4), aberrations of which are associated with PC, within 451 PanIN lesions present in the pancreata of 60 patients. p21(WAF1/CIP1) overexpression was present in the normal ducts of 9% of patients and increased progressively to 16% of patients with PanIN-1A lesions, to 32% of patients with PanIN-1B lesions, 56% of patients with PanIN-2 lesions, 80% of patients with PanIN-3 lesions, and 85% of patients with invasive carcinomas (P < 0.01). p53 and cyclin D1 overexpression occurred predominantly in PanIN-3 lesions (P < 0.01), and loss of DPC4/Smad4 expression occurred predominantly in PanIN-3 lesions and invasive carcinoma (P < 0.01). In addition, p21(WAF1/CIP1) overexpression occurred independently of p53 and DPC4/Smad4 expression within invasive carcinoma and PanIN-3 lesions. Cyclin D1 overexpression or loss of DPC4/Smad4 expression was apparent in 85% of invasive carcinomas but in only 14% of PanIN-2 lesions. These data demonstrate that overexpression of p21(WAF1/CIP1) occurs early in the development of PanIN, before aberrations in p53, cyclin D1, and DPC4/Smad4 expression. p21(WAF1/CIP1) overexpression, independent of p53 and/or DPC4/Smad4 expression, may reflect increased Ras activity, either directly through activating K-ras mutations or as a consequence of HER-2/neu (ERBB2) overexpression, both of which are common in PC and in early events in the development of PanIN. These data support further the current progression model for PC and demonstrate that aberrant expression of key cell cycle regulatory genes may be important in the early development and progression of PanIN.

The operative management of screen-detected breast cancers

BACKGROUND

Mammographic screening for breast cancer not only reduces the overall mortality from breast cancer but allows greater opportunities for breast-conserving operations. The predicted degree of breast conservation is not being realized, but is increasing in centres that have published their results.

METHODS

The operative management of breast cancers diagnosed by BreastScreen Central and Eastern Sydney Screening and Assessment Service were compared between two time periods: January 1988-December 1992 (group 1) and January 1993-December 1995 (group 2). The rate of breast conservation, and other data were compared between the two periods. An attempt was made with multivariate analysis to identify some of the factors that made mastectomy rather than conservation more likely.

RESULTS

There were 723 cancers detected that were suitable for analysis (group 1, n = 273; group 2, n = 450). In group 1 the breast conservation rate was 42.9%; this increased significantly to 60.4% in group 2 (P < 0.001). The data were examined to determine if there was any other factor that had changed over the time periods which might account for the increased rate of breast conservation. The use of pre-operative diagnostic techniques such as fine needle aspirate cytology and core biopsy increased significantly. Multivariate analysis comparing the differences in patient age, diagnostic technique, tumour type, grade, size, location and lymph node status, both independently and compositely did not account for the increase in breast conservation in group 2.

CONCLUSION

The increase in breast conservation is due to other factors such as the surgeons' approach and patient attitude. The use of pre-operative, minimally invasive tissue sampling techniques is increasing.

Endocrine cells of transitional mucosa adjacent to colonic adenocarcinoma

Transitional mucosa (TM) is used to describe mucosa adjacent to colonic adenocarcinoma with characteristic morphological and histochemical features. There is currently much debate about its aetiology. Some suspect it to be premalignant; others view it as a reactive change. Studies have looked at the morphology of TM and the type of mucins secreted by goblet cells within TM. Little work has been done on the third group of cells present in colonic mucosa; the enteroendocrine cells. These cells have many functions concerned predominantly with modulating the local environment. They are thought to be able to influence growth and metabolism. There is growing evidence in animal studies which suggest that hormones present within endocrine cells of colonic mucosa can influence colonic tumour growth rates. In this study endocrine cells stained with histochemical and immunocytochemical techniques were examined under the light microscope. Serotonin immunoreactive cells, the predominating endocrine cells of colonic epithelium, were present in greater numbers within the TM. Their increase was proportional to the increase in height of the mucosa of the TM. The increase was also proportional to the increase in epithelial cell numbers within the mucosa. This suggests that they proliferate together with the other epithelial cells of TM. In conclusion, serotonin containing cells appear to be an integral component of TM.