Adenomyomas of the Gallbladder: An Analysis of Frequency, Clinicopathologic Associations, and Relationship to Carcinoma of a Malformative Lesion

CONTEXT.—

The nature and associations of gallbladder (GB) "adenomyoma" (AM) remain controversial. Some studies have attributed up to 26% of GB carcinoma to AMs.

OBJECTIVE.—

To examine the true frequency, clinicopathologic characteristics, and neoplastic changes in GB AM.

DESIGN.—

Cholecystectomy cohorts analyzed were 1953 consecutive cases, prospectively with specific attention to AM; 2347 consecutive archival cases; 203 totally embedded GBs; 207 GBs with carcinoma; and archival search of institutions for all cases diagnosed as AM.

RESULTS.—

Frequency of AM was 9.3% (19 of 203) in totally submitted cases but 3.3% (77 of 2347) in routinely sampled archival tissue. A total of 283 AMs were identified, with a female to male ratio = 1.9 (177:94) and mean size = 1.3 cm (range, 0.3-5.9). Most (96%, 203 of 210) were fundic, with formed nodular trabeculated submucosal thickening, and were difficult to appreciate from the mucosal surface. Four of 257 were multifocal (1.6%), and 3 of 257 (1.2%) were extensive ("adenomyomatosis"). Dilated glands (up to 14 mm), often radially converging to a point in the mucosa, were typical. Muscle was often minimal, confined to the upper segment. Nine of 225 (4%) revealed features of a duplication. No specific associations with inflammation, cholesterolosis, intestinal metaplasia, or thickening of the uninvolved GB wall were identified. Neoplastic change arising in AM was seen in 9.9% (28 of 283). Sixteen of 283 (5.6%) had mural intracholecystic neoplasm; 7 of 283 (2.5%) had flat-type high-grade dysplasia/carcinoma in situ. Thirteen of 283 cases had both AM and invasive carcinoma (4.6%), but in only 5 of 283 (1.8%), carcinoma arose from AM (invasion was confined to AM, and dysplasia was predominantly in AM).

CONCLUSIONS.—

AMs have all the features of a malformative developmental lesion, and may not show a significant muscle component (ie, the name "adeno-myoma" is partly a misnomer). While most are innocuous, some pathologies may arise in AMs, including intracholecystic neoplasms, flat-type high-grade dysplasia or carcinoma in situ, and invasive carcinoma (1.8%, 5 of 283). It is recommended that gross examination of GBs include serial slicing of the fundus for AM detection and total submission if one is found.

Reappraisal of T1b gallbladder cancer (GBC): clinicopathologic analysis of 473 in situ and invasive GBCs and critical review of the literature highlights its rarity, and that it has a very good prognosis

There are highly conflicting data on relative frequency (2-32%), prognosis, and management of pT1b-gallbladder carcinoma (GBC), with 5-year survival ranging from > 90% in East/Chile where cholecystectomy is regarded as curative, versus < 50% in the West, with radical operations post-cholecystectomy being recommended by guidelines. A total of 473 in situ and invasive extensively sampled GBCs from the USA (n = 225) and Chile (n = 248) were re-evaluated histopathologically per Western invasiveness criteria. 349 had invasive carcinoma, and only 24 were pT1. Seven cases previously staged as pT1b were re-classified as pT2. There were 19 cases (5% of all invasive GBCs) qualified as pT1b and most pT1b carcinomas were minute (< 1mm). One patient with extensive pTis at margins (but pT1b focus away from the margins) died of GBC at 27 months, two died of other causes, and the remainder were alive without disease (median follow-up 69.9 months; 5-year disease-specific survival, 92%). In conclusion, careful pathologic analysis of well-sampled cases reveals that only 5% of invasive GBCs are pT1b, with a 5-year disease-specific survival of > 90%, similar to findings in the East. This supports the inclusion of pT1b in the "early GBC" category, as is typically done in high-incidence regions. Pathologic mis-staging of pT2 as pT1 is not uncommon. Cases should not be classified as pT1b unless extensive, preferably total, sampling of the gallbladder to rule out a subtle pT2 is performed. Critical appraisal of the literature reveals that the Western guidelines are based on either SEER or mis-interpretation of stage IB cases as "pT1b." Although the prognosis of pT1b-GBC is very good, additional surgery (radical cholecystectomy) may be indicated, and long-term surveillance of the biliary tract is warranted.

Integrative molecular characterisation of gallbladder cancer reveals micro-environment-associated subtypes

BACKGROUND & AIMS

Gallbladder cancer (GBC) is the most common type of biliary tract cancer, but the molecular mechanisms involved in gallbladder carcinogenesis remain poorly understood. In this study, we applied integrative genomics approaches to characterise GBC and explore molecular subtypes associated with patient survival.

METHODS

We profiled the mutational landscape of GBC tumours (whole-exome sequencing on 92, targeted sequencing on 98, in total 190 patients). In a subset (n = 45), we interrogated the matched transcriptomes, DNA methylomes, and somatic copy number alterations. We explored molecular subtypes identified through clustering tumours by genes whose expression was associated with survival in 47 tumours and validated subtypes on 34 publicly available GBC cases.

RESULTS

Exome analysis revealed TP53 was the most mutated gene. The overall mutation rate was low (median 0.82 Mut/Mb). APOBEC-mediated mutational signatures were more common in tumours with higher mutational burden. Aflatoxin-related signatures tended to be highly clonal (present in ≥50% of cancer cells). Transcriptome-wide survival association analysis revealed a 95-gene signature that stratified all GBC patients into 3 subtypes that suggested an association with overall survival post-resection. The 2 poor-survival subtypes were associated with adverse clinicopathologic features (advanced stage, pN1, pM1), immunosuppressive micro-environments (myeloid-derived suppressor cell accumulation, extensive desmoplasia, hypoxia) and T cell dysfunction, whereas the good-survival subtype showed the opposite features.

CONCLUSION

These data suggest that the tumour micro-environment and immune profiles could play an important role in gallbladder carcinogenesis and should be evaluated in future clinical studies, along with mutational profiles.

LAY SUMMARY

Gallbladder cancer is highly fatal, and its causes are poorly understood. We evaluated gallbladder tumours to see if there were differences between tumours in genetic information such as DNA and RNA. We found evidence of aflatoxin exposure in these tumours, and immune cells surrounding the tumours were associated with survival.

Inflammatory profiles in Chilean Mapuche and non-Mapuche women with gallstones at risk of developing gallbladder cancer

Chile has high incidence rates of gallbladder cancer globally, particularly among Amerindian women, who also have a high prevalence of gallstones. We examined differences in inflammatory biomarkers between Mapuche and non-Mapuche women from the Chile Biliary Longitudinal Study, a cohort of women with ultrasound-detected gallstones. We randomly selected 200 Mapuche women frequency matched to non-Mapuche women on age and statin use Inflammatory biomarkers were analyzed using a multiplex assay and linear regression to assess associations of a priori markers (CCL20, CXCL10, IL-6, and IL-8) with ethnicity. Novel biomarkers were analyzed using exploratory factor analysis (EFA) and sufficient dimension reduction (SDR) to identify correlated marker groups, followed by linear regression to examine their association with ethnicity. The mean values of IL-8 were higher in Mapuche than non-Mapuche women (P = 0.04), while CCL20, CXCL10, and IL-6 did not differ significantly by ethnicity. EFA revealed two marker groups associated with ethnicity (P = 0.03 and P < 0.001). SDR analysis confirmed correlation between the biomarkers and ethnicity. We found higher IL-8 levels among Mapuche than non-Mapuche women. Novel inflammatory biomarkers were correlated with ethnicity and should be studied further for their role in gallbladder disease. These findings may elucidate underlying ethnic disparities in gallstones and carcinogenesis among Amerindians.

The Chile Biliary Longitudinal Study: A Gallstone Cohort

Gallbladder cancer (GBC) is a highly fatal cancer that can be cured through cholecystectomy if identified early. The presence of gallstones is the primary risk factor for GBC, but few people with gallstones develop GBC. A key question is what drives the development of GBC among persons with gallstones. We initiated the Chile Biliary Longitudinal Study (Chile BiLS) to address this question. From 2016 to 2019, Chile BiLS enrolled 4,726 women aged 50-74 years with ultrasound-detected gallstones from southern-central Chile, accounting for an estimated 36% of eligible women with gallstones in the study area. The median age was 59 years; 25% of the women were Amerindian (Mapuche), 60% were obese, 25% had diabetes, and 6% had cardiovascular disease. Participants will be followed for gallbladder dysplasia or cancer for 6 years. As of April 30, 2020, over 91% of those eligible completed the year 2 follow-up visit. Data being collected include epidemiologic and sociodemographic information, anthropometric measurements, blood pressure, and tooth counts. Biosamples being taken include baseline plasma, buffy coat, red blood cells, serum, blood clot from serum, and PAXgene whole blood (PreAnalytiX GmbH, Hombrechtikon, Switzerland). Complete gallbladder sampling is conducted for most participants undergoing cholecystectomy. The Chile BiLS cohort study will increase our understanding of GBC etiology and could identify potential risk stratification and early detection strategies in high-risk areas.

T2 gallbladder cancer shows substantial survival variation between continents and this is not due to histopathologic criteria or pathologic sampling differences

Published data on survival of T2 gallbladder carcinoma (GBC) from different countries show a wide range of 5-year survival rates from 30-> 70%. Recently, studies have demonstrated substantial variation between countries in terms of their approach to sampling gallbladders, and furthermore, that pathologists from different continents apply highly variable criteria in determining stage of invasion in this organ. These findings raised the question of whether these variations in pathologic evaluation could account for the vastly different survival rates of T2 GBC reported in the literature. In this study, survival of 316 GBCs from three countries (Chile n = 137, South Korea n = 105, USA n = 74), all adequately sampled (with a minimum of five tumor sections examined) and histopathologically verified as pT2 (after consensus examination by expert pathologists from three continents), was analyzed. Chilean patients had a significantly worse prognosis based on 5-year all-cause mortality (HR: 1.89, 95% CI: 1.27-2.83, p = 0.002) and disease-specific mortality (HR: 2.41, 95% CI: 1.51-3.84, p < 0.001), compared to their South Korean counterparts, even when controlled for age and sex. Comparing the USA to South Korea, the survival differences in all-cause mortality (HR: 1.75, 95% CI: 1.12-2.75, p = 0.015) and disease-specific mortality (HR: 1.94, 95% CI: 1.14-3.31, p = 0.015) were also pronounced. The 3-year disease-specific survival rates in South Korea, the USA, and Chile were 75%, 65%, and 55%, respectively, the 5-year disease-specific survival rates were 60%, 50%, and 50%, respectively, and the overall 5-year survival rates were 55%, 45%, and 35%, respectively. In conclusion, the survival of true T2 GBC in properly classified cases is neither as good nor as bad as previously documented in the literature and shows notable geographic differences even in well-sampled cases with consensus histopathologic criteria. Future studies should focus on other potential reasons including biologic, etiopathogenetic, management-related, populational, or healthcare practice-related factors that may influence the survival differences of T2 GBC in different regions.

Mural Intracholecystic Neoplasms Arising in Adenomyomatous Nodules of the Gallbladder: An Analysis of 19 Examples of a Clinicopathologically Distinct Entity

Intracholecystic neoplasms (ICNs) (pyloric gland adenomas and intracholecystic papillary neoplasms, collectively also called intracholecystic papillary/tubular neoplasms) form multifocal, extensive proliferations on the gallbladder mucosa and have a high propensity for invasion (>50%). In this study, 19 examples of a poorly characterized phenomenon, mural papillary mucinous lesions that arise in adenomyomatous nodules and form localized ICNs, were analyzed. Two of these were identified in 1750 consecutive cholecystectomies reviewed specifically for this purpose, placing its incidence at 0.1%. Median age was 68 years. Unlike other gallbladder lesions, these were slightly more common in men (female/male=0.8), and 55% had documented cholelithiasis. All were characterized by a compact multilocular, demarcated, cystic lesion with papillary proliferations and mucinous epithelial lining. The lesions' architecture, distribution, location, and typical size were suggestive of evolution from an underlying adenomyomatous nodule. All had gastric/endocervical-like mucinous epithelium, but 5 also had a focal intestinal-like epithelium. Cytologic atypia was graded as 1 to 3 and defined as 1A: mucinous, without cytoarchitectural atypia (n=3), 1B: mild (n=7), 2: moderate (n=2), and 3: severe atypia (n=7, 3 of which also had invasive carcinoma, 16%). Background gallbladder mucosal involvement was absent in all but 2 cases, both of which had multifocal papillary mucosal nodules. In conclusion, these cases highlight a distinct clinicopathologic entity, that is, mural ICNs arising in adenomyomatous nodules, which, by essentially sparing the "main" mucosa, not displaying "field-effect/defect" phenomenon, and only rarely (16%) showing carcinomatous transformation, are analogous to pancreatic branch duct intraductal papillary mucinous neoplasms.

Gallbladder polyps: Correlation of size and clinicopathologic characteristics based on updated definitions

Background

Different perspectives exist regarding the clinicopathologic characteristics, biology and management of gallbladder polyps. Size is often used as the surrogate evidence of polyp behavior and size of ≥1cm is widely used as cholecystectomy indication. Most studies on this issue are based on the pathologic correlation of polyps clinically selected for resection, whereas, the data regarding the nature of polypoid lesions from pathology perspective -regardless of the cholecystectomy indication- is highly limited.

Methods

In this study, 4231 gallbladders -606 of which had gallbladder carcinoma- were reviewed carefully pathologically by the authors for polyps (defined as ≥2 mm). Separately, the cases that were diagnosed as “gallbladder polyps” in the surgical pathology databases were retrieved.

Results

643 polyps identified accordingly were re-evaluated histopathologically. Mean age of all patients was 55 years (range: 20–94); mean polyp size was 9 mm. Among these 643 polyps, 223 (34.6%) were neoplastic: I. Non-neoplastic polyps (n = 420; 65.4%) were smaller (mean: 4.1 mm), occurred in younger patients (mean: 52 years). This group consisted of fibromyoglandular polyps (n = 196) per the updated classification, cholesterol polyps (n = 166), polypoid pyloric gland metaplasia (n = 41) and inflammatory polyps (n = 17). II. Neoplastic polyps were larger (mean: 21 mm), detected in older patients (mean: 61 years) and consisted of intra-cholecystic neoplasms (WHO’s “adenomas” and “intracholecystic papillary neoplasms”, ≥1 cm; n = 120), their “incipient” version (<1 cm) (n = 44), polypoid invasive carcinomas (n = 26) and non-neoplastic polyps with incidental dysplastic changes (n = 33). In terms of size cut-off correlations, overall, only 27% of polyps were ≥1 cm, 90% of which were neoplastic. All (except for one) ≥2 cm were neoplastic. However, 14% of polyps <1 cm were also neoplastic. Positive predictive value of ≥1 cm cut-off -which is widely used for cholecystectomy indication-, was 94.3% and negative predictive value was 85%.

Conclusions

Approximately a third of polypoid lesions in the cholecystectomies (regardless of the indication) prove to be neoplastic. The vast majority of (90%) of polyps ≥1 cm and virtually all of those ≥2 cm are neoplastic confirming the current impression that polyps ≥1 cm ought to be removed. However, this study also illustrates that 30% of the neoplastic polyps are <1 cm and therefore small polyps should also be closely watched, especially in older patients.

Follicular Cholecystitis: Reappraisal of Incidence, Definition, and Clinicopathologic Associations in an Analysis of 2550 Cholecystectomies

CONTEXT.

Follicular cholecystitis (FC) is a poorly characterized entity.

OBJECTIVE.

To determine its frequency/clinicopathologic associations.

DESIGN.

A total of 2550 cholecystectomy specimens were examined. Two hundred three of these were consecutive routine cholecystectomies submitted entirely for microscopic examination to determine the relative frequency of incidental pathologies in gallbladders (GBs). The remainder had representative sampling. Underlying conditions were nonobstructive pathologies (1270 nonspecific cholecystitis), obstructive (62 distal biliary tract tumors, 35 primary sclerosing cholangitis, and 31 autoimmune pancreatitis), and neoplastic (n = 949). FC was defined as 3 distinct lymphoid follicles (LFs)/centimeter.

RESULTS.

In the GBs totally submitted for microscopic examination, the true frequency of FC was found to be 2.5% (5/203), and in the representatively sampled group, it was 1.9%, with similar frequencies in nonobstructive, obstructive, and neoplastic cases (2.3%, 3.1%, and 1.3%, respectively, P = .77). When the 39 FC in nonneoplastic GBs contrasted with ordinary chronic cholecystitis, they were associated with older age (68 vs 49 years, P < .0001), similar gallstone frequency (68 vs 81%), female/male ratio (2.7 vs 2.6), and wall thickness (4 mm for both). None had lymphoma/parasites/Salmonella infection. Of 17 cases who had undergone gastric biopsy, 5 had chronic gastritis (2 with Helicobacter pylori). Microscopically, the LFs were the main inflammatory process often with minimal intervening inflammation. IgG4-positive plasma cell density was low (<10/high-power field) in 21/24(87.5%) cases.

CONCLUSIONS.

Follicular cholecystitis is seen in 2% of cholecystectomies, typically in significantly older patients, suggesting a deranged immune response. A third of the patients reveal biopsy-proven gastritis. FC does not seem to be associated with autoimmunity, lymphoma, or obstructive pathologies.

Pitfalls in assessing stromal tumor infiltrating lymphocytes (sTILs) in breast cancer

Stromal tumor-infiltrating lymphocytes (sTILs) are important prognostic and predictive biomarkers in triple-negative (TNBC) and HER2-positive breast cancer. Incorporating sTILs into clinical practice necessitates reproducible assessment. Previously developed standardized scoring guidelines have been widely embraced by the clinical and research communities. We evaluated sources of variability in sTIL assessment by pathologists in three previous sTIL ring studies. We identify common challenges and evaluate impact of discrepancies on outcome estimates in early TNBC using a newly-developed prognostic tool. Discordant sTIL assessment is driven by heterogeneity in lymphocyte distribution. Additional factors include: technical slide-related issues; scoring outside the tumor boundary; tumors with minimal assessable stroma; including lymphocytes associated with other structures; and including other inflammatory cells. Small variations in sTIL assessment modestly alter risk estimation in early TNBC but have the potential to affect treatment selection if cutpoints are employed. Scoring and averaging multiple areas, as well as use of reference images, improve consistency of sTIL evaluation. Moreover, to assist in avoiding the pitfalls identified in this analysis, we developed an educational resource available at www.tilsinbreastcancer.org/pitfalls.

[Protocolized referral to endoscopy and Helicobacter pylori detected in stools aimed to decrease endoscopy waiting lists]

Background Chile has one of the highest mortality rates by gastric cancer (GC) worldwide. Primary prevention of GC and detection of pre-neoplastic and early neoplastic lesions should be a national priority. Aim To assess the impact of the protocolization of endoscopy referral and the use of H. pylori stool antigen test (HPSA) in the management of dyspepsia to decrease the waiting list for endoscopy and increase the detection of gastric pre-neoplastic and early neoplastic lesions. Material and Methods We included all patients referred to the Endoscopy Unit of a regional hospital, from January 2015 to December 2017. We also included patients with known pre-neoplastic lesions and all those with first degree relatives with GC. We implemented protocols for referral of patients with dyspepsia considering the use of HPSA test, prioritizing to endoscopy those with a higher risk of GC. Results A total of 4,641 endoscopies and 2,631 HPSA tests were carried out. After the adoption of these protocols, we observed a 52% decrease in the waiting time for endoscopy. The GC detection rate in this period was 1.8 to 3.1 cases per 100 endoscopies. After the adoption of the protocols, we observed a significant increase in early GC detection rate (from none in 2015 to 13% in 2017, p = 0.03). Conclusions The protocolization of the referral for endoscopy associated with widespread use of HPSA test in the management of patients with dyspepsia, are successful strategies to decrease waiting lists for endoscopy and optimize the detection rate of pre-neoplastic lesions and early GC.

Sarcomatoid carcinomas of the gallbladder: clinicopathologic characteristics

Sarcomatoid carcinomas recently came into the spotlight through genetic profiling studies and also as a distinct model of epithelial-mesenchymal transition. The literature on sarcomatoid carcinomas of gallbladder is limited. In this study, 656 gallbladder carcinomas (GBC) were reviewed. Eleven (1.7%) with a sarcomatoid component were identified and analyzed in comparison with ordinary GBC (O-GBC). Patients included 9 females and 2 males (F/M = 4.5 vs. 3.9) with a mean age-at-diagnosis of 71 (vs. 64). The median tumor size was 4.6 cm (vs. 2.5; P = 0.01). Nine patients (84%) presented with advanced stage (pT3/4) tumor (vs. 48%). An adenocarcinoma component constituting 1-75% of the tumor was present in nine, and eight had surface dysplasia/CIS; either in situ or invasive carcinoma was present in all cases. An intracholecystic papillary-tubular neoplasm was identified in one. Seven showed pleomorphic-sarcomatoid pattern, and four showed subtle/bland elongated spindle cells. Three had an angiosarcomatoid pattern. Two had heterologous elements. One showed few osteoclast-like giant cells, only adjacent to osteoid. Immunohistochemically, vimentin, was positive in six of six; P53 expression was > 60% in six of six, keratins in six of seven, and p63 in two of six. Actin, desmin, and S100 were negative. The median Ki67 index was 40%. In the follow-up, one died peri-operatively, eight died of disease within 3 to 8 months (vs. 26 months median survival for O-GBC), and two were alive at 9 and 15 months. The behavior overall was worse than ordinary adenocarcinomas in general but was not different when grade and stage were matched. In summary, sarcomatoid component is identified in < 2% of GBC. Unlike sarcomatoid carcinomas in the remainder of pancreatobiliary tract, these are seldom of the "osteoclastic" type and patients present with large/advanced stage tumors. Limited data suggests that these tumors are aggressive with rapid mortality unlike pancreatic osteoclastic ones which often have indolent behavior.

Abstract B29: ZNF516 a potential tumor suppressor gene candidate is implied in tumor progression in cervical cancer

Background: In Cervical Cancer (CC) the role of HPV is fundamental; however, not all HPV infected women will develop this disease. Therefore, other mechanisms, such as silencing of tumor suppressor genes (TSG), could be implied in cervical carcinogenesis. In a previous study, we constructed methylation microarrays, where we found promoter aberrant hypermethylation of ZNF516 gen in CC, postulating it as TSG candidate. The aim of this study was to characterizer ZNF516 role in cervical carcinogenesis and cell cycle.

Materials and methods: ECT1 E6/E7 (immortalized normal squamous epithelia cell line) and three CC cell lines: SiHa, C-4I and C-33A were cultivated for experiments. ZNF516 expression was determined by qRT-PCR and western blot. Treatment with 10 μM 5-aza-2′deoxycytidine (5- aza) was performed to evaluate a possible epigenetic regulation. Transfection with pCMV6-ZNF516-GFP (ZNF516) and pCMV6-GFP (Empty) was carried out in C-33A cell line through lipofection followed by G418 selection to obtain stable transfection. Viability and clonogenic assay was performed to evaluate transfected cell behaviour. Also, immnunohistochemical analysis was performed in 509 cervical biopsy tissues (55 normal; 188 low-squamous intraepithelial lesions; 205 high- squamous intraepithelial lesions and 57 squamous cervical cancers).

Results: ZNF516 mRNA expression was significantly downregulated in SiHa (p&lt;0.01) and C-33A (p&lt;0.001) respect to ECT1 E6/E7. Western blot showed a deregulated protein expression of ZNF516 in all CC cell lines. After treatment with 5-aza, mRNA (p&lt;0.05) and protein expression of ZNF516 of all CC cell lines were restored. ZNF516 transfected C-33A showed a significant colony formation (p&lt;0.01) and viability (p&lt;0.01) decrease compared with C-33A transfected with the empty vector. Nuclear expression of ZNF516 in cervical biopsies showed a diminished expression in SCC respect to normal epithelia (p&lt;0.001)

Conclusions: There is a clear ZNF516 dysregulation in CC cell lines, and the inactivation mechanism seem to be methylation. Restored expression of ZNF516 in C-33A cell line modifies the tumor phenotype, decreasing cellular viability and colony formation. These results suggest that ZNF516 could be a TSG, and its inactivation promotes CC developing.

Citation Format: Carmen Gloria Ili, Tamara Viscarra, Juan Carlos Araya, Jaime Lopez, Barbara Mora, Javier Retamal, Enrique Bellolio, Susana Aedo, Juan Carlos Roa, Priscilla Brebi. ZNF516 a potential tumor suppressor gene candidate is implied in tumor progression in cervical cancer. [abstract]. In: Proceedings of the AACR Precision Medicine Series: Cancer Cell Cycle - Tumor Progression and Therapeutic Response; Feb 28-Mar 2, 2016; Orlando, FL. Philadelphia (PA): AACR; Mol Cancer Res 2016;14(11_Suppl):Abstract nr B29.

The Gene Expression Status of the PI3K/AKT/mTOR Pathway in Gastric Cancer Tissues and Cell Lines

The PI3K/AKT/mTOR pathway plays a crucial role in the regulation of multiple cellular functions including cell growth, proliferation, metabolism and angiogenesis. Emerging evidence has shown that deregulation of this pathway has a role promoting gastric cancer (GC). The aim was to assess the expression of genes involved in this pathway by qPCR in 23 tumor and 23 non-tumor gastric mucosa samples from advanced GC patients, and in AGS, MKN28 and MKN45 gastric cancer cell lines. Results showed a slight overexpression of PIK3CA, PIK3CB, AKT1, MTOR, RPS6KB1, EIF4EBP1 and EIF4E genes, and a slightly decreased PTEN and TSC1 expression. In AGS, MKN28 and MKN45 cells a significant gene overexpression of PIK3CA, PIK3CB, AKT1, MTOR, RPS6KB1 and EIF4E, and a significant repression of PTEN gene expression were observed. Immunoblotting showed that PI3K-β, AKT, p-AKT, PTEN, mTOR, p-mTOR, P70S6K1, p-P70S6K1, 4E-BP1, p-4E-BP1, eIF4E and p-eIF4E proteins were present in cell lines at different levels, confirming activation of this pathway in vitro. This is the first time this extensive panel of 9 genes within PI3K/AKT/mTOR pathway has been studied in GC to clarify the biological role of this pathway in GC and develop new strategies for this malignancy.

[Predictive value of breast imaging report and database system (BIRADS) to detect cancer in a reference regional hospital]

BACKGROUND

To validate the BIRADS in mammography, the calculation of its predictive value in each center is required, as recommended by the American College of Radiology.

AIM

To determine the predictive value of the BIRADS system in our center.

MATERIAL AND METHODS

All ultrasound guided needle percutaneous biopsies, performed at our center between 2006 and 2010 were reviewed. Predictive value, sensitivity, specificity and diagnostic accuracy of BIRADS were calculated, with a confidence interval of 95%.

RESULTS

Of 1,313 biopsies available, 1,058 met the inclusion criteria. Fifty eight percent of biopsies were performed to women with mammographies classified as BIRADS 4 or 5. The presence of cancer in mammographies classified as BIRADS 0 was 4%. The prevalence of cancer for mammographies BIRADS 1, 2, 3, 4 and 5 were 0, 3, 2.7, 17.7 and 72.4% respectively. The positive and negative predictive values of BIRADS classification were 55 and 92 % respectively.

CONCLUSIONS

In our institution BIRADS classification 4 and 5 has a high positive predictive value for detecting cancer as in developed countries.

miR-101-2, miR-125b-2 and miR-451a act as potential tumor suppressors in gastric cancer through regulation of the PI3K/AKT/mTOR pathway

BACKGROUND

Gastric cancer (GC) is a deadly malignancy worldwide. In the past, it has been shown that cellular signaling pathway alterations play a crucial role in the development of GC. In particular, deregulation of the PI3K/AKT/mTOR pathway seems to affect multiple GC functions including growth, proliferation, metabolism, motility and angiogenesis. Targeting alterations in this pathway by microRNAs (miRNAs) represents a potential therapeutic strategy, especially in inhibitor-resistant tumors. The objective of this study was to evaluate the expression of 3 pre-selected miRNAs, miR-101-2, miR-125b-2 and miR-451a, in a series of primary GC tissues and matched non-GC tissues and in several GC-derived cell lines, and to subsequently evaluate the functional role of these miRNAs.

METHODS

Twenty-five primary GC samples, 25 matched non-GC samples and 3 GC-derived cell lines, i.e., AGS, MKN28 and MKN45, were included in this study. miRNA and target gene expression levels were assessed by quantitative RT-PCR and western blotting, respectively. Subsequently, cell viability, clone formation, cell death, migration and invasion assays were performed on AGS cells.

RESULTS

miR-101-2, miR-125b-2 and miR-451a were found to be down-regulated in the primary GC tissues and the GC-derived cell lines tested. MiRNA mimic transfections significantly reduced cell viability and colony formation, increased cell death and reduced cell migration and invasion in AGS cells. We also found that exogenous expression of miR-101-2, miR-125b-2 and miR-451a decreased the expression of their putative targets MTOR, PIK3CB and TSC1, respectively.

CONCLUSIONS

Our expression analyses and in vitro functional assays suggest that miR-101-2, miR-125b-2 and miR-451a act as potential tumor suppressors in primary GCs as well as in GC-derived AGS cells.

[Prognostic factors for gastric cancer without lymph node involvement]

BACKGROUND

The absence of lymph node involvement (N0) in gastric cancer is associated with a better survival. However some N0 gastric tumors still have a bad prognosis.

AIM

To study demographic and morphological variables associated with prognosis in N0 gastric carcinoma.

MATERIAL AND METHODS

Review of pathological records of a regional general hospital, identifying patients with a N0 gastric cancer surgically excised between 1986 and 2003.

RESULTS

In the study period, 459 gastrectomies were performed for gastric cancer and in 32%, the tumor was devoid of lymph node involvement. These later patients were followed for a median of 64 months with a 71% five years actuarial survival. Bivariate analysis identified age, tumor size, gastric wall infiltration, pathological type according to Lauren and Ming, lymphovascular involvement, number of lymph nodes excised and TNM stage as prognostic values Multivariate analysis disclosed the level of gastric wall infiltration, the presence of a poorly differentiated tumor, lymphatic vascular involvement, number of excise lymph nodes and tumor size as independent prognostic factors.

CONCLUSIONS

N0 gastric tumors are found in 32% of gastrectomies for gastric cancer and have a 71% five years actuarial survival. Gastric wall infiltration, pathological degree of differentiation tumor size and lymphovascular involvement are independent prognostic factors.

[Concordance between Gleason scores of trans rectal biopsies and the surgical piece of radical prostatectomy]

BACKGROUND

Gleason pathological score in prostate cancer is an important prognostic indicator. However, the concordance between the score of trans rectal needle biopsies and the final score of the surgical piece may be variable.

AIM

To analyze the concordance between Gleason scores of trans rectal prostate biopsies and those of the surgical piece obtained after prostatectomy.

MATERIAL AND METHODS

Retrospective analysis of 168 pathological records of radical prostatectomies, performed between 1993 and 2009. All these patients had also a trans rectal biopsy performed previously. Patients with less than 12 tissue cylinders obtained during the trans rectal biopsy or incomplete data were not included in this analysis.

RESULTS

Sixty eight percent of trans rectal biopsies had Gleason scores that were concordant with those of the surgical piece. The score was higher or lower in 27 and 10% of biopsies, respectively.

CONCLUSIONS

Gleason scores of trans rectal biopsies and those of the surgical piece were concordant in 68% of cases in this series of pathological records.

[Mesenteric cryptococcal lymphadenitis: report of one case]

Cryptococcosis is an invasive mycotic infection caused by Cryptococcus neoformans, an encapsulated, yeast-like fungus. It is considered an opportunist infection, since it mainly affects immunocompromised subjects. However there are isolated reports of the infection in immunocompetent subjects. Cryptococcal infection of intra-abdominal organs or tissues is extremely rare. We report a 21-year-old HIV positive male that, during the treatment of a meningeal cryptococcosis, presented a clinical picture of an acute abdomen suggesting acute appendicitis. The patient was operated, finding enlarged mesenteric lymph nodes forming conglomerates and a macroscopically normal appendix. The conglomerated lymph nodes and the appendix were excised. The pathological study of the surgical piece revealed an intra abdominal cryptococcal lymphadenitis and a normal appendix.

[Hepatocarcinoma with sarcomatoid transformation: case report]

Hepatocarcinoma with sarcomatoid transformation is uncommon. It presents clinically with inverted exclamation markeucocytosis and fever, resembling a liver abscess. We report a 40 year-old male that presented pain in the right upper quadrant and fever. Abdominal imaging showed an hypodense image in the liver that resembled a liver abscess. The patient was subjected to a percutaneous drainage obtaining 150 ml of an hemorrhagic fluid whose culture was negative. The clinical picture persisted and the patient was subjected to a right hepatectomy. The pathological study of the surgical piece disclosed a hepatocarcinoma with sarcomatoid transformation. The patient was discharged sixteen days after surgery.

Prognostic factors of phyllodes tumor of the breast

The phyllodes tumor is characterized by its tendency to recur locally and occasionally to metastasize. The purpose of the present paper was to assess the prognostic value of clinical-morphological characteristics in patients with phyllodes tumor. Forty-seven cases of phyllodes tumors was studied; the World Health Organization classification was used and follow up was obtained. A total of 51%, 28% and 21% of the tumors were classified as benign, borderline and malignant, respectively. The adherence (P = 0.01), size >10 cm (P = 0.001), high mitotic activity (P = 0.03), infiltrative tumor margin (P = 0.0002) and type of surgery in malignant tumors (P = 0.02) proved to be good predictors of relapse. The presence of pain (P = 0.03), postmenopausal status (P < 0.04), heavy cellular pleomorphism (P = 0.007), high mitotic activity (P = 0.002), tumoral grade (P = 0.006) and metastasis (P < 0.00001) were prognostic factors of poor survival. Tumoral grade and some clinical-morphological characteristics of patients with phyllodes tumors have a significant impact on the prediction of its biological behavior.

Promoter methylation profile in gallbladder cancer

BACKGROUND

Methylation in the promoter region of genes is an important mechanism of inactivation of tumor suppressor genes. Our objective was to analyze the methylation pattern of some of the genes involved in carcinogenesis of the gallbladder, examining the immunohistochemical expression of proteins, clinical features, and patient survival time.

METHODS

Twenty cases of gallbladder cancer were selected from the frozen tumor bank. The DNA extracted was analyzed by means of a methylation-specific polymerase chain reaction test for the CDKN2A (p16), MLH1, APC, FHIT, and CDH1 (E-cadherin) genes. Morphological and clinical data and follow-up information were obtained.

RESULTS

All cases were in an advanced stage: histologically moderate or poorly differentiated tumors (95%). Methylation of the promoter area of genes was observed in 5%, 20%, 30%, 40%, and 65% of cases, and an altered immunohistochemical pattern (AIP) in 5%, 35%, 21%, 25%, and 66% for the MLH1, CDKN2A, FHIT, APC, and CDH1 genes, respectively. The Kappa concordance index between methylation of the promoter area and AIP for the MLH1 and CDH1 genes was very high (K > 0.75) and substantial for APC (K > 0.45). No correlation was found between survival time and the methylation of the genes studied.

CONCLUSIONS

The high frequency of gene methylation (with the exception of MLH1) and the high agreement between AIP and methylation of the gene promoter area for the MLH1, APC, and CDH1 genes suggest that the inactivation of tumor suppressor genes and of the genes related to the control of cellular proliferation through this mechanism is involved in gallbladder carcinogenesis.

[Association between Helicobacter pylori genotype and the severity of gastritis in infected adults]

BACKGROUND

The damaging capacity of Helicobacter pylori is variable and depends, in part, on its genetic polymorphism.

AIM

To study H pylori genes vacA, cagA and iceA and the relationship of these genotypes with the features of acute damage in chronic gastritis.

MATERIAL AND METHODS

Gastric endoscopic biopsies were obtained in 75 adults for pathological study and genetic typification of H pylori by specific PCR.

RESULTS

In only 64 cases, complete information was available. In 53 of these, there was H pylori infection demonstrated by PCR. Twenty one percent had infection by two or more H pylori strains, vacA gene had genotypes s2/m2, s1/m1 and s1/m2 in 36, 25 and 8% of cases respectively, cagA gene was present in 49% of infected patients. iceA gene had genotypes iceA 1 ad iceA 2 in 15 and 60% of patients respectively. The presence of cagA or alleles s1/m1 and s1/m2 of vacA gene was directly correlated with polymorphonuclear infiltration and the severity of epithelial damage. The genotype s2/m2 of vacA gene was significantly associated with a milder or absent mucosal damage. No association was found between iceA alleles and the pathological features of gastritis.

CONCLUSIONS

Alleles of vacA and cagA genes of H pylori are associated with the severity of gastric mucosal damage.

[Promoter methylation profile in gastric cancer]

BACKGROUND

Promoter genomic DNA methylation is an important inactivation mechanism of tumor suppressor genes. This genetic-molecular pathway for cancer may separate a subset of patients with different prognoses and eventually different responses to specific therapies.

AIM

To analyze the methylation pattern of important genes related to different carcinogenic mechanisms in patients with gastric cancer (GC) and the relationship with its morphological features and biological behavior.

MATERIAL AND METHODS

Forty-seven fresh-frozen GC samples were selected. The methylation-specific PCR (MSP) test was used to analyze promoter methylation status for genes MLH1, CDKN2A (p16), APC, CDH1 (Cadherin E) and FHIT. Follow-up and complete morphological features were obtained for all cases.

RESULTS

We found methylation in at least one of the genes studied in 83% of the cases. The frequencies of promoter hypermethylation of MLH1, CDKN2A, APC, CDH1 and FHIT were 31%, 43%, 46%, 80% y 62%, respectively. We found a relationship between APC methylation and good histological differentiation (p =0.03); CDH1 methylation with diffuse type by Lauren and 3 or more metastasic lymph nodes (p <0.05); FHIT, CDKN2A and CDH1 methylation and female condition (p <0.04). We also found a non-significant relationship between CDKN2A methylation and better survival (p =0.07).

CONCLUSIONS

The high frequency promoter methylation found confirms its importance in gastric carcinogenesis. The finding of alterations in the methylation pattern of genes studied and its association with prognostic factors is a helpful tool in the search for new criteria in clinical and therapeutic decision making.

Microsatellite instability in preneoplastic and neoplastic lesions of the gallbladder

BACKGROUND

Gallbladder cancer is very common in Chile and is the leading cause of cancer deaths in women aged over 40 years. However, there is limited information about the molecular changes involved in its pathogenesis. Microsatellite analysis was performed using polymerase chain reaction (PCR)-based assays to identify genetic loci that were altered in neoplastic and preneoplastic conditions of early and advanced gallbladder cancer. Our findings were then correlated with clinicopathological variables and survival time.

METHODS

We selected 59 surgical specimens of gallbladder adenocarcinomas (29 early cancers and 30 advanced cancers) and 22 surgical specimens from patients with chronic cholecystitis from a high-risk area for gallbladder cancer (Temuco, Chile). Laser capture microdissection (LCM) was used to harvest tumor cells and preneoplastic lesions. Microsatellite analysis was performed using 13 different markers. The tumors and preneoplastic lesions were also examined with immunohistochemistry for hMLH1, hMSH2, and hMSH6.

RESULTS

We found that 10% (6/59) of gallbladder cancers showed high-frequency microsatellite instability (MSI-H), with identical proportions in both early and advanced cancers. In premalignant lesions adjacent to the six MSI-H tumors, we detected instability in two of six examples of intestinal metaplasia (33%) and five of six examples of dysplasia (83%). All MSI-H cases showed an altered pattern with the antibodies studied. MSI status was not associated with survival or other clinicopathological features. No MSI or immunohistochemical alterations were found in the chronic cholecystitis group.

CONCLUSIONS

Microsatellite instability was observed in equal proportions in early and late cancers, and it was also found in premalignant lesions, indicating that inactivation of mismatch repair genes occurs early in gallbladder carcinogenesis.

[Inactivation of CDKN2A gene (p16) in gallbladder carcinoma]

BACKGROUND

The CDKN2A gene encodes a cyclin dependent kinase inhibitor, p16, which promotes cell cycle arrest. Methylation of the promoter region transcriptionally inactivates the gene.

AIM

To study the relationship between methylation status of the prometer region of p16 gene, the immunohistochemical expression of p16 and clinical and morphological features of gallbladder carcinoma.

MATERIAL AND METHODS

We analyzed the methylation status of the promoter region of the CDKN2A gene in gallbladder adenocarcinomas using methylation specific PCR (MSP). We also used microsatellite markers near the CDKN2A gene to detect allelic imbalance (AI) and examined the tumors by immunohistochemistry (IHC) for p16 expression.

RESULTS

Of 38 gallbladder adenocarcinomas analyzed by IHC, 11 cases (29%) were negative for p16 protein. Nine (24%) had methylation of the promoter region of the CDKN2A gene. Twenty nine cases were negative for methylation, but four (14%) of these 29 exhibited AI at one or more of the microsatellite markers. CDKN2A promoter methylation was not associated with microsatellite instability (MSI-H).

CONCLUSIONS

The inactivation of CDKN2A by methylation and/or deletion might play an important role in gallbladder carcinogenesis.

[Promoter methylation profile in breast cancer]

BACKGROUND

Genomic DNA methylation, mutations and allelic deletions explain the inactivation of genes involved in cell proliferation and cell cycle control mechanisms.

AIM

To analyze the methylation pattern of important genes related to different carcinogenic mechanisms in patients with breast cancer and the relationship with its biological behavior.

MATERIAL AND METHODS

Seventy fresh-frozen breast cancer samples were selected. The methylation specific PCR (MSP) test was used to analyze promoter methylation status for genes CDKN2A (p16), hMLH1, APC, CDH1 (Cadherin E) and FHIT.

RESULTS

We found methylation in at least one of the genes studied in 88% of cases and in 3 or more genes in 40.5% of cases. The frequencies of promoter hypermethylation of CDKN2A, hMLH1, APC, CDH1 and FHT were 41.4%, 11.4%, 52.9%, 70% and 42.9%, respectively. We found a relationship between CDKN2A methylatlon and better survival (p=0.002). CDH1 methylation and poor histological differentiation (p=0.007), hMLH1 methylation and non-Mapuche ethnicity (p=-0.03), APC methylation and larger tumor size (p<0.05), FHIT methylatton and lack of estrogen rectptor IHC expression (p<0.05).

CONCLUSIONS

The high frequency of promoter methylation in patients with breast cancer confirms its role in breast carcinogenesis. The finding of alterations in the methylation pattern of genes studied and its association with prognostic factors is a helpful tool in the search of new criteria for clinical and therapeutic decision making.

[Genetic changes in chronic gastritis: study of microsatellite instability and loss of heterozygosity]

BACKGROUND

Multifocal chronic gastritis, associated to intestinal metaplasia, is considered a preneoplastic lesion, closely associated to intestinal type gastric cancer.

AIM

To study the frequency of microsatellite instability (MSI) and loss of heterozygosity (LOH) in areas of chronic gastritis and intestinal metaplasia in gastric biopsies of patients without cancer.

MATERIAL AND METHODS

Gastric biopsy samples from 34 patients without cancer (22 with multifocal atrophic gastritis and 12 with diffuse antral gastritis), were studied. Glands from areas of chronic gastritis and intestinal metaplasia and lymphocytes, were collected using laser microdissection of paraffin embedded samples. The analysis of 15 mono and dinucleotide microsatellites was used to assess LOH and MSI.

RESULTS

LOH and MSI were found in some of the markers in 55% (12/22) and 59% (13/22) of cases with intestinal metaplasia, respectively. Only one of 12 areas with diffuse atrophic gastritis had MSI and a different area had LOH (p < 0.05 or less, when compared with areas of multifocal atrophic gastritis). Three areas of normal epithelium in patients with multifocal atrophic gastritis, also had alterations. Most of these alterations were concordant with adjacent areas with intestinal metaplasia.

CONCLUSIONS

LOH and MSI was found in areas of intestinal metaplasia in more than half of the studied cases and in few areas of atrophic gastritis without intestinal metaplasia. These findings suggest that genotypic alterations may precede phenotypic modifications and that intestinal metaplasia is a preneoplastic lesion.

[Microsatellite instability and loss of heterozygosity in neoplastic and preneoplastic gastric lesions]

BACKGROUND

Gastric cancer is the leading cause of cancer deaths in the general population in Chile, with mortality rates as high as 33.7 per 105 in males in the IX region. A chain of genetic and morphological events precedes the intestinal type of gastric carcinoma. One of them is the called multifocal atrophic gastritis often associated with intestinal metaplasia.

AIM

To study the frequency of microsatellite instability (MSI) and loss of heterocigozity (LOH) in neoplastic and preneoplastic lesions of gastric carcinoma, especially intestinal metaplasia.

MATERIAL AND METHODS

Ninety four gastric cancer biopsies were studied using laser capture microdissection, to obtain well defined cell populations from paraffin-embedded tissues: lymphocytes (control DNA), intestinal metaplasia and gastric cancer areas. Primer flanking microsatellite 15 highly polymorphic regions were used to study MSI and LOH. Radioactive PCR products were electrophoresed and exposed for autoradiography.

RESULTS

LOH was observed in 83% of gastric carcinomas and in 54% areas containing intestinal metaplasia. The most commonly altered regions were the CA repeat associated with the p53 gene and the 3p21 region. High grade MSI was observed in 11.7% of gastric cancer preparations and 17% of intestinal metaplasia associated to cancer with MSI-H phenotype.

CONCLUSIONS

MSI and LOH were frequently observed in intestinal metaplasia glands in patients with gastric carcinoma. The frequency of MSI-H phenotype in gastric patients was slightly lower than the one described in sporadic colorectal cancer not associated to HNPCC. The high incidence of genetic lesions in intestinal metaplasia area, support the idea that intestinal metaplasia is a genetically highly unstable cell population.

[Point mutation of TP53 suppressor gene in pre-neoplastic and neoplastic lesions of the stomach]

BACKGROUND

In the current model for the development of gastric cancer, regions of multifocal atrophic gastritis give rise to intestinal metaplasia, dysplasia and finally, adenocarcinoma.

AIM

To study the frequency and characteristics of TP53 gene mutations in preneoplastic and neoplastic lesions of the stomach.

MATERIAL AND METHODS

DNA sequencing of the TP53 gene was performed in 46 patients with gastric carcinoma. Normal mucosa, intestinal metaplasia and invasive adenocarcinoma tissues were obtained by scraping 6-micron histological sections from formalin-fixed and paraffin-embedded tissue.

RESULTS

DNA sequencing of exons 5-9 of the TP53 gene demonstrated a mutation in 31% of patients. These findings were seen both in tumoral tissue (13 cases) and in intestinal metaplasia (2 cases). Most mutations were found in exons 5 and 8, and the majority of them were transitions (10 out of 19 mutations).

DISCUSSION

Patients with gastric cancer showed a frequency of TP53 mutations similar to that previously communicated in populations with low gastric cancer risk. Moreover, there was a predominance of transitions, genetic alterations that are identified with carcinogenesis associated with N-nitrosamine compounds. Finally, mutations of TP53 gene were detected in areas of intestinal metaplasia.

[Incipient gallbladder carcinoma. Clinical and pathological study and prognosis in 196 cases]

BACKGROUND

There is little information about the behavior of early gallbladder carcinoma.

AIM

To report the clinical and pathological features of 196 patients with early gallbladder carcinoma.

MATERIAL AND METHODS

All patients with gallbladder cancer diagnosed between 1988 and 1997 were reviewed. In 703 of 829 patients, there was information about clinical features and follow up, and were included in this study. All gallbladders were subjected to a complete mapping. When neoplastic cells involved only the mucosa or muscular layer, the tumors were considered as early.

RESULTS

One hundred ninety six patients had an early carcinoma (161 women, aged 57.5 years and 35 male, aged 63.4 years). One hundred twenty eight tumors were located in the mucosa and 68 in the muscular layer. Patients with tumors involving the mucosa were younger than those with tumors involving the muscular layer. All tumors were adenocarcinomas, 66% were well differentiated and 32% moderately differentiated. Tumors were not visible macroscopically in 132 cases. Five and 10 years survival was 92%. Subjects of less than 40 years old had a 100% survival at 5 years. A hepatic and lymph node resection was done in 12 patients with tumors infiltrating the muscular layer but in only one, the tumor infiltrated the liver. No difference in survival was observed when a simple cholecystectomy or radical surgery was done.

CONCLUSIONS

Nearly 25% of gallbladder carcinomas can be classified as early and its diagnosis requires a directed study. Simple cholecystectomy is curative for this type of gallbladder cancer.

[Findings in surgical reinterventions for cancer of the gallbladder in patients with and without preoperative chemotherapy and radiotherapy]

BACKGROUND

The usefulness of surgery in the treatment of gallbladder cancer has not been clearly established. The benefits of chemo and radiotherapy are similarly dubious.

AIM

To report the pathological findings in patients subjected to surgical reinterventions for gallbladder cancer.

PATIENTS AND METHODS

We report 54 patients with gallbladder cancer that were subjected to a second surgical intervention for resection of liver segments IVb and V and lymph nodes corresponding to the liver hilar, portal, peripancreatic, celiac artery and periaortic territories. Thirteen of these patients were subjected to preoperative chemo-radiotherapy (4500 Gy and 5-fluouracil 500 mg/m2).

RESULTS

Lymph node metastases were found in 25 and 38%, and liver metastases in 25 and 28% of patients with or without chemo-radiotherapy respectively. The most frequent pathological findings attributed to radiation in the liver were fatty infiltration in 75% of cases, vascular transformation in 83% of cases and minimal periportal lymphocyte infiltration in 40% of cases. Lymph nodes were atrophic in 67% of cases and had foci of cortical necrosis in 46% of cases. Three cases had regional lymph node and liver metastases. Most tumor cells were viable.

CONCLUSIONS

No differences in the number of lymph node or liver metastases were observed between patients with and without chemo-radiotherapy. No effect of the treatment on residual tumor was observed either.

[P53 tumor suppressor gene in digestive neoplasms]

Malignant diseases of the digestive tract cause more than 50% of deaths due to cancer in Chile. There is a high incidence of gastric and gallbladder cancer and an increasing frequency of colorectal cancer. P53 tumor suppressor gene has a great importance in carcinogenesis and its alterations are specially important in digestive tract tumors such as colorectal cancer. There is contradictory evidence about the frequency of p53 gene or protein alterations or their biological significance. There is little information about p53 in Chile and it is mostly limited to immunohistochemical studies. This revision analyzes the frequency of p53 alterations in digestive tract tumors in Chile, using immunohistochemical and molecular biology methods. A special emphasis is given to the prognostic importance of this gene.

[p53 gene mutation in cancer of the colon and rectum]

BACKGROUND

Genetic events associated to colorectal carcinoma are well characterized, but there is scanty information about this issue in Chilean subjects.

AIM

To determine the frequency and distribution of exons 5, 6, 7, 8 and 9 mutations and the immunohistochemical expression of p53 gene in biopsy samples of colorectal carcinoma.

MATERIAL AND METHODS

p53 gene exons 5, 6, 7, 8 and 9 were directly sequenced in 42 biopsy samples of colorectal carcinoma. Immunohistochemical expression of p53 was determined in 35 samples.

RESULTS

Thirty one discrete mutations (12 transitions, 11 transversions and 8 insertions) were observed in 21 samples (60%). Nine samples had mutations in exon 5, twelve samples had mutations in exon 6, seven samples had mutations in exon 7 and three samples had mutations in exons 8 and 9. Immunohistochemical expression of p53 protein was observed in 18 of 35 cases. There was a high correlation between the genetic alteration and immunohistochemistry, when p53 was expressed in more the 20% of cells. The positive and negative predictive values of p53 expression were 87 and 80% respectively. There was a non significant lower mortality among patients with mutations in their biopsies.

CONCLUSIONS

These results confirm the involvement of p53 gene mutations in colonic carcinogenesis. Immunohistochemical methods for the detection of p53 protein have a high predictive value.

[Carcinoma hepatocellular. Description of verified clinical characteristics in a region of Southern Chile]

BACKGROUND

Hepatocellular carcinoma is the most frequent primary tumor of the liver. It is associated to chronic liver diseases and has a high prevalence in some regions of Africa and Asia.

AIM

To describe the clinical characteristics of patients with hepatocellular carcinoma, admitted to two hospitals of the IX region of southern Chile.

MATERIAL AND METHODS

Prospective study of 29 consecutive patients admitted to two hospitals in Temuco, Chile. Clinical features, laboratory values and viral markers were analyzed.

RESULTS

Eighteen patients were male and ages ranged from 29 to 75 years old. The most frequent presenting symptom was abdominal pain in 21 patients. Seven subjects had a history of alcoholism. Serum bilirubin values ranged from 0.1 to 15.8 mg/dl, alkaline phosphatases ranged from 171 to 3476 U/l, ASAT from 24 to 5400 U/l and alpha feto protein from 1.4 to 350 ng/ml. Two patients had a positive hepatitis B surface antigen and all had negative hepatitis C virus antibodies. Mean tumoral diameter was 9.6 cm and the most common presentation was nodular. Mean survival after the diagnosis was 6.3 months.

CONCLUSIONS

These patients with hepatocellular carcinoma have a low frequency of positive viral markers and tumors of large sizes on presentation.

[Helicobacter pylori and chronic gastritis: relationship between infection and inflammatory activity in a high risk population for gastric cancer]

BACKGROUND

Helicobacter pylori has been involved in gastric epithelial cell damage and gastric gland loss or atrophy.

AIMS

To evaluate role of Helicobacter pylori infection in acute and chronic changes of chronic gastritis in a high gastric cancer-risk population.

MATERIAL AND METHODS

200 patients with chronic gastritis were selected from pathological files of Temuco Hospital. A complete histopathological protocol was fulfilled considering the presence of infection by Helicobacter pylori-like-organism (HLO), acute and chronic inflammatory infiltrate, epithelial cell damage and epithelial cell regeneration.

RESULTS

82% of patients showed infection by HLO. Moreover, this infection reached a frequency of 92.7% in gastric ulcer patients and 94.4% in duodenal ulcer patients. A statistically significant positive correlation was found between HLO infection and polymorphonuclear infiltrate, lymphocytic infiltrate, mucus depletion and epithelial regenerative activity. There was not a statistical correlation between HLO infection and atrophy. Finally, 90% of patients with multifocal atrophic gastritis and 100% of patients with diffuse antral gastritis had HLO infection.

CONCLUSIONS

HLO gastric infection frequently caused acute inflammatory changes in gastric mucosa with chronic gastritis. Sometimes these changes were severe, with marked polymorphonuclear migration throughout epithelium and severe epithelial cell damage. Recovery of these changes could be considered as a goal in Helicobacter pylori eradication therapy decision.

[Gastric cancer and tumor growth regulation. Study of cell proliferation markers and protein complex p53/p21WAF1/CIP1/mdm-2]

BACKGROUND

p53/p21WAF1/CIP1 and mdm-2 proteins play an important role in cell cycle regulation. The study of the pathogenesis of gastric cancer is important to understand how these tumors progress during their natural history.

AIM

To study the relationship between the immunohistochemical expression of p53/p21WAF1/CIP1 and mdm-2 and cell proliferation in gastric cancer.

MATERIAL AND METHODS

Fifty one gastrectomy specimens with gastric cancer were studied using immunohistochemistry for p53/p21WAF1/CIP1 and mdm-2. Cell proliferation was determined by immunolabelling with PCNA and Ki67 antigens. Mitosis figures were counted in 10 high power microscopic fields.

RESULTS

Patients from whom gastric cancer specimens were obtained had a mean age of 59.3 years. Ki67 and mitosis counting showed the highest correlation index with proliferation indexes studied. No correlation was found between the expression of protein complex p53/p21WAF1/CIP1 and mdm-2 and morphological characteristics of gastric tumors. Mdm-2 protein overexpression was the only marker that showed an independent correlation with cell proliferation. Moreover, mdm-2 positive tumors showed the highest proliferation indexes when p53 was not immunohistochemically over-expressed, as determined by PCNA labelling index.

CONCLUSIONS

In gastric cancer, a direct correlation between mdm-2 overexpression and cell proliferation was observed. Moreover, the fact that mdm-2 positive tumors showed the highest cell proliferation when p53 was not overexpressed, entitles us to hypothesize that mdm-2 overexpression could play a major role in gastric carcinogenesis.

Gallbladder cancer in a high risk area: morphological features and spread patterns

BACKGROUND/AIMS

Gallbladder carcinoma is one of the most frequent malignant tumors in Chile. The aim of this paper is to show our experiences in gallbladder carcinoma.

METHODOLOGY

Six-hundred-sixty-nine cases of gallbladder carcinoma were included in this prospective study; 557 females (83.5%) and 112 males (16.5%). In 466 cases (70%), diagnosis was carried out in the cholecystectomy sample, 45 cases were partial cholecystectomies and 158 cases were metastases of gallbladder carcinoma.

RESULTS

Ninety-eight per cent of the cases were adenocarcinomas, and in 85% of the cases gallstones were observed. Thirty-seven per cent of the primary tumors were macroscopically inapparent. One-hundred-thirty-one cases (29%) were early carcinomas and 323 cases (71%) were advanced carcinomas. A relationship between differentiation grade and infiltration level (p=0.0001) was observed. Lymph-node metastasis was found in 18.5%, 4.5% and 3.3% in the first, second and third lymph-node barriers respectively. Muscular tumors presented no lymph-node metastasis, while in serosal tumors lymph node metastasis reached 62% (p=0.04). Hepatic tumor infiltration was observed in 11%, 19% and 38% of muscular, subserosal and serosal tumors.

CONCLUSIONS

The high frequency of inapparent carcinomas, gallstones and inflammatory changes of the vesicular wall are elements that make the pre-operative diagnosis of gallbladder carcinoma difficult. Differentiation grade and infiltration level are the most reliable prognostic factors in gallbladder carcinoma. Lymph-node metastasis or liver tumor infiltration are infrequent in early gallbladder carcinoma.

Preoperative Chemoradiotherapy in the Treatment of Gallbladder Cancer

Gallbladder cancer is generally associated with a poor prognosis, with local recurrence being the main pattern of failure. In an attempt to improve on the present status of management, we evaluated a prospective Phase II study involving preoperative 5-fluorouracil and radiation. Among 27 eligible patients with a potentially resectable gallbladder cancer detected after cholecystectomy, 18 were treated with preoperative radiation (4500 cGy; 180 cGy/fraction, 5 days/week) concurrent with a continuous infusion of 5-fluorouracil (350 mg/m2/day, days 1–5 and 21–25). Toxicity included leukopenia (8 patients) and thrombocytopenia (7 patients). Delay in surgery due to hematological toxicity was seen in 6 patients. Of the 18 patients, 15 underwent a reoperation. Resection was performed in 13 (86%). Pathologic findings after reoperation revealed residual tumor in both liver and lymph nodes in 3 patients. At a median follow-up of 24 months, 7 patients are alive. Among the patients who died after curative resection, local recurrence was demonstrated in only 1. This is the first report concerning preoperative chemoradiation in gallbladder cancer. To assess its effect on survival, a prospective randomized trial will be necessary.

Preoperative chemoradiotherapy in the treatment of gallbladder cancer

Gallbladder cancer is generally associated with a poor prognosis, with local recurrence being the main pattern of failure. In an attempt to improve on the present status of management, we evaluated a prospective Phase II study involving preoperative 5-fluorouracil and radiation. Among 27 eligible patients with a potentially resectable gallbladder cancer detected after cholecystectomy, 18 were treated with preoperative radiation (4500 cGy; 180 cGy/fraction, 5 days/week) concurrent with a continuous infusion of 5-fluorouracil (350 mg/m2/day, days 1-5 and 21-25). Toxicity included leukopenia (8 patients) and thrombocytopenia (7 patients). Delay in surgery due to hematological toxicity was seen in 6 patients. Of the 18 patients, 15 underwent a reoperation. Resection was performed in 13 (86%). Pathologic findings after reoperation revealed residual tumor in both liver and lymph nodes in 3 patients. At a median follow-up of 24 months, 7 patients are alive. Among the patients who died after curative resection, local recurrence was demonstrated in only 1. This is the first report concerning preoperative chemoradiation in gallbladder cancer. To assess its effect on survival, a prospective randomized trial will be necessary.

Peritoneal pseudomyxoma in a child with a gallbladder Peutz-Jeghers-like hamartomatous polyp: a case report

A 2-year, 6-month-old boy with peritoneal pseudomyxoma had a hamartomatous Peutz-Jeghers-like polyp in the gallbladder. The morphological pattern of the polyp was very characteristic of what is usually considered an hamartomatous polyp. The patient presently reported has no clinical characteristics of Peutz-Jeghers syndrome. The peritoneal pseudomyxoma creates differential diagnostic problems with well-differentiated mucinous adenocarcinoma.

Hepatic Helicobacter species identified in bile and gallbladder tissue from Chileans with chronic cholecystitis

BACKGROUND & AIMS

Cancer of the gallbladder is the number one cause of cancer mortality in Chilean women. Incidence rates for this tumor vary widely on a worldwide basis, being approximately 30 times higher in high-risk than in low-risk populations, suggesting that environmental factors such as infectious microorganisms, carcinogens, and nutrition play a role in its pathogenesis. Because several Helicobacter sp. colonize the livers of animals and induce hepatitis, the aim of this study was to determine whether Helicobacter infection was associated with cholecystitis in humans.

METHODS

Bile or resected gallbladder tissue from 46 Chileans with chronic cholecystitis undergoing cholecystectomy were cultured for Helicobacter sp. and subjected to polymerase chain reaction (PCR) analysis using Helicobacter-specific 16S ribosomal RNA primers.

RESULTS

Recovery of Helicobacter sp. from frozen specimens was unsuccessful. However, by PCR analysis, 13 of 23 bile samples and 9 of 23 gallbladder tissues were positive for Helicobacter. Eight of the Helicobacter-specific PCR amplicons were sequenced and subjected to phylogenetic analysis. Five sequences represented strains of H. bilis, two strains of "Flexispira rappini" (ATCC 49317), and one strain of H. pullorum.

CONCLUSIONS

These data support an association of bile-resistant Helicobacter sp. with gallbladder disease. Further studies are needed to ascertain whether similar Helicobacter sp. play a causative role in the development of gallbladder cancer.

[Tumor invasion in gallbladder cancer. Importance of blood vascular tumor infiltration diagnosis]

BACKGROUND

The infiltration of venous blood vessels in gallbladder carcinoma and its importance as a prognostic factor has not been well studied. Victoria blue stain has been used to identify vascular involvement in gastric and thyroidal carcinomas.

AIM

To assess blood vessel infiltration using Victoria blue stain in gallbladder carcinomas.

MATERIAL AND METHODS

One hundred forty eight samples of gallbladder carcinomas, coming from 24 men and 123 women aged 60.4 +/- 12.2 years old, were studied. They were stained with Victoria blue stain to quantify blood vessel invasion.

RESULTS

Twenty nine percent of tumors had blood vessel infiltration, 61% had lymph vessel and 20% had perineural infiltration. Lymph vessel or perineural involvement was found in 81% and 31% of those tumors with blood vessel infiltration, respectively. Perineural infiltration was associated with lymph or vascular involvement in 93 and 40% of tumors, respectively. None of the early carcinomas had blood vessel infiltration, whereas 33% of advanced tumors had this type of infiltration (p < 0.001). No differences in vascular infiltration were observed according to the differentiation of the tumor.

CONCLUSIONS

Blood vessel infiltration was observed only in advanced gallbladder carcinomas and was tightly related to the degree of gallbladder wall infiltration. The presence of perineural infiltration was the best marker of lymph or blood vessel infiltration.

Double immunostaining for p53 and molecular chaperone hsp72/73 in gastric carcinoma

AIMS

To examine the relation between the expression of p53 protein and the chaperone heat shock protein (hsp)72/73 in a population at high risk for gastric carcinoma, using single and double immunohistochemistry, and to compare the expression of these two proteins with clinicopathological features.

METHODS

Monoclonal antibodies were used to investigate the expression of p53 protein and hsp72/73 in 46 human gastric carcinomas. A double immunohistochemical technique was used in cases that showed p53/hsp72/73 coexpression.

RESULTS

p53 immunoreactivity was present in 11 tumours (24%), and hsp72/73 immunostaining was observed in 22 cases (48%). p53 expression was observed as nuclear staining in tumoral cells. hsp72/73 expression was demonstrated mainly as cytoplasmic staining, but six tumours also showed focal weak nuclear staining. Seven cases showed p53 and hsp72/73 coexpression with immunoreactivity for both proteins in the same neoplastic cells, three of them with focal areas of nuclear coexpression. p53 expression was seen more frequently in cases that showed a high intensity (+ + +) of hsp72/73 staining. No significant association was observed between the expression of the two proteins and clinicopathological features.

CONCLUSIONS

More than half of our cases may have some impairment in p53 protein growth suppressive function, as a result of p53 gene alterations or complex formation. The positive correlation between p53 expression and intensity of hsp72/73 supports the postulate of a p53 regulating function for the chaperone hsp72/73. A high intensity of hsp72/73 immunohistochemical staining could be used as an indirect marker of p53 gene abnormalities.