Diagnosis of hereditary non-polyposis colorectal cancer

Male Breast Cancer: Current Scenario and Future Perspectives

Male breast cancer (MBC), one of the rare types of cancer among men where the global incidence rate is 1.8% of all breast cancers cases with a yearly increase in a pace of 1.1%. Since the last 10 years, the incidence has been increased from 7.2% to 10.3% and the mortality rate was decreased from 11% to 3.8%. Nevertheless, the rate of diagnoses has been expected to be around 2.6% in the near future, still there is a great lack in studies to characterize the MBC including the developed countries. Based on our search, it is evidenced from the literature that the number of risk factors for the cause of MBC are significant, which includes the increase in age, family genetic history, mutations in specific genes due to various environmental impacts, hormonal imbalance and unregulated expression receptors for specific hormones of high levels of estrogen or androgen receptors compared to females. MBCs are broadly classified into ductal and lobular carcinomas with further sub-types, with some of the symptoms including a lump or swelling in the breast, redness of flaky skin in the breast, irritation and nipple discharge that is similar to the female breast cancer (FBC). The most common diagnostic tools currently in use are the ultrasound guided sonography, mammography, and biopsies. Treatment modalities for MBC include surgery, radiotherapy, chemotherapy, hormonal therapy, and targeted therapies. However, the guidelines followed for the diagnosis and treatment modalities of MBC are mostly based on FBC that is due to the lack of prospective studies related to MBC. However, there are distinct clinical and molecular features of MBC, it is a need to develop different clinical methods with more multinational approaches to help oncologist to improve care for MBC patients.

Neuroendocrine Differentiation, Microsatellite Instability, and Tumor-infiltrating Lymphocytes in Advanced Colorectal Cancer With BRAF Mutation

BACKGROUND

Approximately 10% of metastatic colorectal cancer (mCRC) cases will harbor the BRAF p.V600E mutation (BRAF-mCRC) and have been associated with a poor prognosis. Although they are usually considered a unique clinical entity, biologic heterogeneity has been described. We performed an extensive clinicopathologic study of a multicenter series of BRAF-mCRC to highlight differences between tumors with microsatellite instability (MSI) and microsatellite stable tumors, focusing on both inflammatory profiles and neuroendocrine differentiation.

METHODS

We included 59 BRAF-mCRC cases and collected the clinical data (ie, surgery, treatment, and follow-up). We evaluated MSI status, budding, lympho-angioinvasion, neuroinvasion, extent of active stroma, CD3⁺ and CD8⁺ intratumoral and peritumoral lymphocytes, programmed cell death ligand 1, p53, Ki-67, synaptophysin, and CDX2 expression.

RESULTS

The 22 MSI BRAF-mCRC cases were associated with the right side (P < .0001), an expansive grown pattern (P < .01), programmed cell death ligand 1 expression (P < .0001), high CD8 T-cell content (P = .0001), and lymph node metastases (P < .029). The 37 MSS BRAF-mCRC cases were characterized by a greater stromal component (P = .0002), pulmonary metastases (P = .095), and p53 and synaptophysin immunoreactivity (P = .004 and P = .001, respectively). Univariate analysis demonstrated that MSI and a high CD8 T-cell content were associated with a 34% (hazard ratio [HR], 0.66; 95% confidence interval [CI], 0.34-1.28; P = .2) and 33% (HR, 0.67; 95% CI, 0.45-0.99; P = .04) reduction in the risk of death, respectively. The combined presence of MSI and CD8 T-cell content decreased the hazard of mortality ≤ 63% (HR, 0.37; 95% CI, 0.14-0.97; P = .2), which was slightly reduced after multivariate analysis.

CONCLUSION

A simultaneous evaluation of MSI, CD8 T-cell content, and neuroendocrine markers could allow for the identification of subsets of BRAF-mCRC with a different prognosis and potential eligibility for specific treatments.

Genetic Testing for Hereditary Nonpolyposis Colorectal Cancer (HNPCC)

Hereditary nonpolyposis colorectal cancer (HNPCC), also called Lynch syndrome, is an autosomal dominant cancer syndrome that confers an elevated risk of early-onset colorectal cancer (CRC) and increased lifetime risk for other cancers of the endometrium, stomach, small intestine, hepatobiliary system, kidney, ureter, and ovary. Lynch syndrome accounts for up to 3% of all CRC, making it the most common hereditary colorectal cancer syndrome. Germline mutations in methyl-directed mismatch repair (MMR) genes give rise to microsatellite instability (MSI) in tumor DNA. Lynch syndrome is most frequently caused by pathogrenic variants in the mismatch repair genes MLH1, MSH2, MSH6, and PMS2. Germline mutations in MLH1 and MSH2 account for approximately 90% of detected mutations in families with Lynch syndrome. Pathogenic vatiants in MSH6 have been reported in approximately 7-10% of families with Lynch syndrome. Pathogenic variants in PMS2 account for fewer than 5% of mutations in families with Lynch syndrome. This unit presents a comprehensive molecular genetic testing strategy for Lynch syndrome including MSI analysis, next generation sequencing (NGS)-based targeted sequence analysis, PCR-based Sanger sequencing and microarray-based comparative genomic hybridization (array-CGH). © 2017 by John Wiley & Sons, Inc.

Microsatellite instability use in mismatch repair gene sequence variant classification

Inherited mutations in the DNA mismatch repair genes (MMR) can cause MMR deficiency and increased susceptibility to colorectal and endometrial cancer. Microsatellite instability (MSI) is the defining molecular signature of MMR deficiency. The clinical classification of identified MMR gene sequence variants has a direct impact on the management of patients and their families. For a significant proportion of cases sequence variants of uncertain clinical significance (also known as unclassified variants) are identified, constituting a challenge for genetic counselling and clinical management of families. The effect on protein function of these variants is difficult to interpret. The presence or absence of MSI in tumours can aid in determining the pathogenicity of associated unclassified MMR gene variants. However, there are some considerations that need to be taken into account when using MSI for variant interpretation. The use of MSI and other tumour characteristics in MMR gene sequence variant classification will be explored in this review.

Microsatellite instability status in gastric cancer: a reappraisal of its clinical significance and relationship with mucin phenotypes

BACKGROUND

Gastric cancers with microsatellite instabilities (MSI) have been reported to be associated with favorable prognosis. However, the significance of the effect of MSI on the clinicopathological features, as well as its association with mucin phenotype, remains unclear.

METHODS

MSI status was assessed in 414 cases of gastric cancer using polymerase chain reaction analysis of five microsatellite loci, as recommended by National Cancer Institution criteria. The expression of mucins (MUC5AC, MUC6, MUC2, and CD10) was assessed.

RESULTS

Out of 414 total cases of gastric cancer, 380 (91.7%), 11 (2.7%), and 23 (5.6%) were microsatellite stable (MSS), low-level MSI (MSI-L), and high-level MSI (MSI-H), respectively. Compared to MSS/MSI-L, MSI-H gastric cancers were associated with older age (p=0.010), tumor size (p=0.014), excavated gross (p=0.042), intestinal type (p=0.028), aggressive behaviors (increase of T stage [p=0.009]), perineural invasion [p=0.022], and lymphovascular emboli [p=0.027]). MSI-H gastric cancers were associated with tumor necrosis (p=0.041), tumor-infiltrating lymphocytes (≥2/high power field, p<0.001), expanding growth patterns (p=0.038), gastric predominant mucin phenotypes (p=0.028), and MUC6 expression (p=0.016). Tumor necrosis (≥10% of mass, p=0.031), tumor-infiltrating lymphocytes (p<0.001), intestinal type (p=0.014), and gastric mucin phenotypes (p=0.020) could represent independent features associated with MSI-H gastric cancers. MSI-H intestinal type gastric cancers had a tendency for poor prognosis in univariate analysis (p=0.054) but no association in Cox multivariate analysis (p=0.197).

CONCLUSIONS

Our data suggest that MSI-H gastric cancers exhibit distinct aggressive biologic behaviors and a gastric mucin phenotype. This contradicts previous reports that describe MSI-H gastric cancer as being associated with favorable prognosis.

Hereditary non-polyposis colorectal cancer: identification of mutation carriers and assessing pathogenicity of mutations

Hereditary non-polyposis colorectal cancer (HNPCC), also referred to as Lynch syndrome, is an autosomal dominantly inherited disorder that is characterized by susceptibility to colorectal cancer and extracolonic malignancies, in particular endometrial cancer. HNPCC is caused by pathogenic mutations in the mismatch repair (MMR) genes, which play an important role in maintaining genomic stability during DNA replication. Identification of MMR gene mutation carriers is important as this enables them to enrol in surveillance programmes, thus reducing their risk of cancer and increasing survival. Clinical criteria as well as non-clinical criteria have been formulated to select patients for mutation analysis. In this paper we review the approaches used to select patients for mutation analysis. Mutation analysis in the MMR genes may yield mutations of which the pathogenic nature is unclear. Criteria to determine the pathogenicity of such variants are discussed, as well as differences in design of functional assays to assess pathogenicity.

Genetic testing for hereditary nonpolyposis colorectal cancer (HNPCC)

Hereditary nonpolyposis colorectal cancer (HNPCC) is an autosomal dominant cancer syndrome that confers an elevated risk of early-onset colorectal cancer (CRC) and increased lifetime risk for other cancers of the endometrium, stomach, small intestine, hepatobiliary system, kidney, ureter, and ovary. HNPCC accounts for up to 5% of all CRC, making it the most common hereditary colorectal cancer syndrome. Germline mutations in methyl-directed mismatch repair (MMR) genes give rise to microsatellite instability (MSI) in tumor DNA. HNPCC is most often associated with mutations in the MLH1 gene on 3p21, the MSH2 gene on 2p21, and to a lesser extent MSH6 on 2p16. This unit presents a comprehensive molecular and genetic screening strategy for HNPCC mutations in the MLH1, MSH2, and MSH6 genes, including analysis of MSI, mutation scanning by denaturing high-pressure liquid chromatography (DHPLC), and DNA sequencing analysis.

Classifying MLH1 and MSH2 variants using bioinformatic prediction, splicing assays, segregation, and tumor characteristics

Reliable methods for predicting functional consequences of variants in disease genes would be beneficial in the clinical setting. This study was undertaken to predict, and confirm in vitro, splicing aberrations associated with mismatch repair (MMR) variants identified in familial colon cancer patients. Six programs were used to predict the effect of 13 MLH1 and 6 MSH2 gene variants on pre-mRNA splicing. mRNA from cycloheximide-treated lymphoblastoid cell lines of variant carriers was screened for splicing aberrations. Tumors of variant carriers were tested for microsatellite instability and MMR protein expression. Variant segregation in families was assessed using Bayes factor causality analysis. Amino acid alterations were examined for evolutionary conservation and physicochemical properties. Splicing aberrations were detected for 10 variants, including a frameshift as a minor cDNA product, and altered ratio of known alternate splice products. Loss of splice sites was well predicted by splice-site prediction programs SpliceSiteFinder (90%) and NNSPLICE (90%), but consequence of splice site loss was less accurately predicted. No aberrations correlated with ESE predictions for the nine exonic variants studied. Seven of eight missense variants had normal splicing (88%), but only one was a substitution considered neutral from evolutionary/physicochemical analysis. Combined with information from tumor and segregation analysis, and literature review, 16 of 19 variants were considered clinically relevant. Bioinformatic tools for prediction of splicing aberrations need improvement before use without supporting studies to assess variant pathogenicity. Classification of mismatch repair gene variants is assisted by a comprehensive approach that includes in vitro, tumor pathology, clinical, and evolutionary conservation data.

Assay validation for identification of hereditary nonpolyposis colon cancer-causing mutations in mismatch repair genes MLH1, MSH2, and MSH6

Hereditary nonpolyposis colon cancer (HNPCC, Online Mendelian Inheritance in Man (OMIM) 114500) is an autosomal dominant disorder that is genetically heterogeneous because of underlying mutations in mismatch repair genes, primarily MLH1, MSH2, and MSH6. One challenge to correctly diagnosing HNPCC is that the large size of the causative genes makes identification of mutations both labor intensive and expensive. We evaluated the usefulness of denaturing high performance liquid chromatography (DHPLC) for scanning mismatch repair genes (MLH1, MSH2, and MSH6) for point mutations, small deletions, and insertions. Our assay consisted of 51 sets of primers designed to amplify all exons of these genes. All polymerase chain reaction reactions were amplified simultaneously using the same reaction conditions in a 96-well format. The amplified products were analyzed by DHPLC across a range of optimum temperatures for partial fragment denaturation based on the melting profile of each specific fragment. DNA specimens from 23 previously studied HNPCC patients were analyzed by DHPLC, and all mutations were correctly identified and confirmed by sequence analysis. Here, we present our validation studies of the DHPLC platform for HNPCC mutation analysis and compare its merits with other scanning technologies. This approach provides greater sensitivity and more directed molecular analysis for clinical testing in HNPCC.

Review article: the potential of combinational regimen with non-steroidal anti-inflammatory drugs in the chemoprevention of colorectal cancer

Non-steroidal anti-inflammatory drugs are chemopreventive agents in colorectal cancer. Non-steroidal anti-inflammatory drugs do not, however, offer complete protection against adenoma and carcinoma development. There is increasing interest in combining non-steroidal anti-inflammatory drugs with agents that target specific cell signalling pathways in malignant and premalignant cells. This review aims to describe the current knowledge regarding the efficacy of peroxisome proliferator-activated receptor-gamma ligands, cholesterol synthesis inhibitors (statins), epidermal growth factor signalling inhibitors and tumour necrosis factor-related apoptosis-inducing ligand against colorectal neoplasms and the rationale for combining these drugs with non-steroidal anti-inflammatory drugs to improve efficacy in the chemoprevention of colorectal cancer, a PUBMED computer search of the English language literature was conducted to identify relevant papers published before July 2004. Peroxisome proliferator-activated receptor-gamma ligands and statins, both in clinical use, reduce the growth rate of human colon cancer cells in vitro and in rodents models. In vitro, preclinical in vivo and clinical studies have shown efficacy of epidermal growth factor signalling inhibition in colorectal cancer. In vitro, tumour necrosis factor-related apoptosis-inducing ligand induces apoptosis in human colon cancer cells, but not in normal cells. These drugs have all been shown to interact with non-steroidal anti-inflammatory drugs in colorectal cancer cells and/or in rodent models. Combinational regimen are a promising strategy for the chemoprevention of colorectal cancer and should be further explored.

Application of genetics to the prevention of colorectal cancer

A first-degree relative of an individual with colorectal cancer is on average at about a twofold increased risk. This could not occur without there being strong underlying risk factors that are correlated in relatives. About 90% of colorectal cases occur in people who are above median familial/genetic risk, so there is great potential to use genetics to prevent colorectal cancer. Two rare inherited syndromes have been identified: familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC). The former appears to be mostly due to mutations in the APC gene, and the latter to mutations in mismatch repair (MMR) genes, so it would be better named as hereditary mismatch repair deficiency (HMRDS). By fully characterising a population-based series of early-onset cases, we have shown that MMR gene mutation carriers and their relatives can be more efficiently identified by characterising the tumours of early-onset cases, independently of their cancer family history, using immunohistochemistry (IHC)-not microsatellite instability (MSI) testing. This identifies the specific MMR gene likely to be involved, reducing the costs of mutation testing. Identification of genetically susceptible individuals using the tumour phenotype of affecteds, rather than family cancer history, could become the standard approach of cancer genetic services in the twenty-first century, and could lead to cancer prevention in individuals who are at a high genetic risk when young. There is an urgent need for research on the efficacy and optimisation of surveillance procedures in these high-risk individuals, and identification of the environmental, lifestyle and other genetic factors that exacerbate, or ameliorate, risk in mutation carriers.

Rare ductal adenocarcinoma of the pancreas in patients younger than age 40 years

BACKGROUND

Pancreatic ductal adenocarcinomas (PDACs) are extremely rare before age 40 years. The objective of the current study was to determine whether the features of PDACs in patients age < 40 years differ from those in older patients. The authors reviewed the literature and their own files.

METHODS

The cases reported in the literature were evaluated to determine their precise diagnoses and characteristic features. In a series of 439 PDACs from the authors' files, tumors in patients age < 40 years were identified, and their clinicopathologic features and certain genetic features were compared with those in a selected group of patients age > 40 years.

RESULTS

Of 71 pancreatic carcinomas reported in patients age < 40 years, only 20 fully qualified as PDACs. The remaining tumors represented malignancies other than PDACs, such as pancreatoblastoma, solid-pseudopapillary neoplasms, acinar cell carcinomas, and endocrine tumors. PDACs in patients age < 20 years were the absolute exception and commonly were associated with risk factors such as Peutz-Jeghers syndrome, hereditary pancreatic cancer syndrome, and preceding radiotherapy. In the authors' series of patients, there were 6 PDACs and 4 PDAC variants in patients age < 40 years (0.2%), all in male patients. These tumors compared well with the PDACs in patients age > 40 years in their pathologic and molecular findings. Three patients were age < or = 20 years, and 2 of those patients had a mucinous component with MUC2 positivity.

CONCLUSIONS

The incidence of PDACs in patients age < 40 years was approximately 0.3%, and the incidence in patients age < 20 years was 0.1%. Their clinicopathologic findings were comparable to those in patients age > 40 years, but they seemed to include more variants, particularly mucinous carcinomas. In addition, PDACs in younger patients frequently appeared to be associated with genetic factors.

Pancreatic mucinous noncystic (colloid) carcinomas and intraductal papillary mucinous carcinomas are usually microsatellite stable

Pancreatic mucinous noncystic (colloid) carcinomas (MNCC) differ from the usual ductal adenocarcinomas in their mucin expression profile and share with many extrapancreatic mucinous carcinomas the expression of MUC2. Because mucinous carcinomas are frequently associated with mutations of the DNA mismatch repair genes, causing them to exhibit the so-called mutator phenotype, we decided to investigate whether MNCCs of the pancreas are characterized by microsatellite instability (MSI). Twelve carcinomas with a mucinous phenotype (8 mucinous noncystic carcinomas, 3 intraductal papillary-mucinous carcinomas with an invasive muconodular component, and 1 ductal adenocarcinoma with an extensive mucinous noncystic component) and 11 ductal adenocarcinomas were immunostained with monoclonal antibodies to the mismatch repair gene products hMLH1, hMSH2, and hMSH6. For MSI analysis, DNA was isolated from microdissected tissue, and five primary microsatellites (BAT 25, BAT 26, D5S346, D17S250, and D2S123) were analyzed. MSI was diagnosed in case a novel allele was found, compared with the normal tissue. The criterion for LOH was a 75% signal reduction. All carcinomas tested exhibited nuclear expression of mismatch repair gene products, except for one MNCC that also showed MSI at the molecular level. The data suggest that pancreatic carcinomas with a mucinous phenotype (MUC2+/MUC1-) do not appear to normally exhibit mutations in the mismatch repair genes and therefore differ in their carcinogenesis from those in other organs.

Challenge in the differentiation between attenuated familial adenomatous polyposis and hereditary nonpolyposis colorectal cancer: case report with review of the literature

The clinical differentiation between hereditary nonpolyposis colorectal cancer (HNPCC) and attenuated familial adenomatous polyposis (AFAP) is very difficult. The 62-yr-old proband presented with duodenal adenocarcinoma. His history of subtotal colectomy for colon cancer, the rarity of duodenal adenocarcinoma in the general population, and his family history of colon cancer made us suspect that he might have FAP. We investigated this family by obtaining medical records and performing gene analysis. The proband had only 10 adenomatous colon polyps when he underwent subtotal colectomy for the cancer, so classic FAP was excluded. His family history included rectal cancer in his brother at 69 yr of age, colon cancer in his mother at 75 yr, and colon cancer in one maternal cousin at 42 yr. Three months after we started to study this family, the proband's 32-yr-old son presented with rectal cancer. His family fulfilled the Amsterdam criteria for HNPCC, but AFAP could not be excluded. Upon gene testing, the proband was negative for APC gene germline mutation, which made AFAP highly unlikely. Moreover, high microsatellite instability (MSI) was detected in his adenomas and cancer tissues. The fulfillment of Amsterdam criteria, the exclusion of FAP and AFAP, and the high MSI established the diagnosis of HNPCC in this family. We also summarize the differences between FAP, AFAP, and HNPCC; extend the graphic description of the MSI mechanism; and propose a diagnostic strategy for HNPCC.

MLH1 and MSH2 protein immunohistochemistry is useful for detection of hereditary non-polyposis colorectal cancer in young patients

AIMS

Hereditary non-polyposis colorectal cancer is related to germline mutations of DNA mismatch repair genes MLH1 and MSH2, which result in microsatellite instability and loss of protein expression of the corresponding mutated gene in the tumour tissue.

METHODS AND RESULTS

MLH1 and MSH2 protein expression was studied by immunohistochemistry in paraffin-embedded surgical samples of 100 colorectal adenocarcinomas occurring before 50 years of age. Absence of tumour cell nuclear staining with positive internal control (normal mucosa, lymphoid follicles) was considered negative. Loss of MLH1 or MSH2 expression was found in 20 cases with microsatellite instability in 15 cases. Twelve of these patients had a family history of colorectal cancer. Compared with MLH1- and MSH2-positive cases, MLH1- or MSH2-deficient colorectal adenocarcinomas were significantly associated on multivariate analysis with a younger age (38 vs. 43 years, P;0.0224), a larger tumour size (60 +/- 6 vs. 46 +/- 2 mm, P=0.0291), an expanding margin (85% vs. 51%, P=0.0159), a higher number of tumour-infiltrating lymphocytes assessed by CD3 immunostaining (202 +/- 48 vs. 33 +/- 4 CD3+ lymphocytes/10 high-power fields, P=0.0039), and a grade 2 Crohn's like lymphoid reaction (70% vs. 9%, P=0.0037). The two groups were not different for tumour site, differentiation, pTNM stage, vascular and perineural invasion, peripheral adenomatous residue, and 5-year survival rates.

CONCLUSIONS

MLH1- or MSH2-deficient colorectal carcinomas of young patients exhibit pathological and molecular features similar to hereditary non-polyposis colorectal cancer. This suggests that MLH1 and MSH2 immunohistochemistry is valuable for detecting hereditary non-polyposis colorectal cancer in young patients.

Microsatellite instability: application in hereditary non-polyposis colorectal cancer

Colorectal cancer (CRC) is a significant cause of mortality in Western populations. About 15% of CRC patients report a family history of the disease. Studies on individuals with a genetic predisposition to CRC have been responsible for significant advances in the understanding of this disease. Thus, although developments in molecular biology have been mainly restricted to a minority of individuals with a hereditary background, information obtained from this group may affect the diagnosis and therapy of sporadic CRCs as well. Deficiency in the DNA mismatch repair (MMR) system results in microsatellite instability (MSI). Individuals from hereditary non-polyposis colorectal cancer (HNPCC) kindreds with germline mutations in genes involved in MMR may benefit from clinical screening programs. The higher frequency of MSI in HNPCC than in sporadic tumours suggests that involvement of MMR genes in sporadic adenomas may be uncommon. Consequently

Familial colorectal cancer: pathology and molecular characteristics

Appropriate management of familial colorectal cancer revolves around the diagnosis of the underlying genetic syndrome. This necessitates an interdisciplinary approach allowing integration of clinical, morphological, and molecular evidence that may involve several members of the same family. Genetic disorders express themselves over time, whereas clinical investigation of family members is likely to be episodic. Generic features of hereditary colorectal cancer syndromes include a positive family history, early age at onset, multiple neoplasms, and extracolonic lesions of either a developmental or neoplastic nature. Deriving a complete description of a genetic disorder is hampered by the need to trace and obtain tissue samples from many institutions. This review examines the usefulness of tissue-based investigations, both morphological and molecular, in raising the suspicion of familial colorectal cancer, providing a definitive tissue diagnosis and contributing to the larger body of diagnostic evidence. The account focuses on the two most well-studied syndromes--familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC)--but consideration is also given to less well-understood syndromes. Some of these, notably hyperplastic polyposis and mixed polyposis, may closely mimic FAP or HNPCC.

Colorectal cancer before the age of 40: a case-control study

PURPOSE

Colorectal adenocarcinoma before the age of 40 is uncommon, and its prognosis is controversial, with many studies reporting a worse prognosis than in older patients and others showing no difference. The current study compared two groups of patients who had surgical resection for colorectal adenocarcinoma.

METHODS

The case group was composed of 34 patients younger than 40 (34 +/- 4) years. Detailed pathologic prognosis factors, tumor cell proliferation measured by proliferating cell nuclear antigen, survival, family history, and predisposing conditions were analyzed. Results were compared with a control group constituted of 34 patients older than 65 (75 +/- 6) years matched by gender, cancer site, and Dukes stage.

RESULTS

Tumor differentiation, presence of vascular and perineural neoplastic invasion, tumor growth pattern, tumor cell proliferation measured by proliferating cell nuclear antigen count, and survival according to the Kaplan-Meier method were not significantly different between younger and older patients. The only difference between the two groups was a higher prevalence of family history and predisposing conditions for colorectal cancer in younger patients (23 vs. 3 percent; P = 0.03).

CONCLUSION

This case-control study documents that pathologic features and prognosis of colorectal adenocarcinoma are comparable in patients younger than 40 years compared with older patients for identical stages. The higher prevalence of positive family history in younger patients suggests a different genetic background compared with older patients.

Pathologic characteristics of colorectal cancer in the elderly: a retrospective study of 947 surgical cases

To determine the pathologic characteristics of colorectal cancer in the very old, a retrospective study of 947 consecutive Japanese patients aged > or =65 with 1,039 lesions were examined. Pathologic findings in the very old group (>85 years, n = 140) were compared with those in the younger groups; young-old group (65-74 years, n = 352) and middle-old group (75-84 years, n = 455). Although male:female ratio significantly decreased with advancing age, reaching 1:1.8 in the very old group, the relative odds of colorectal cancer in men were higher than that in women in all age groups. In the very old group, cancer of the proximal colon (proximal to the splenic flexure) accounted for 52% in women and 37% in men, being significantly higher than those in the younger groups. Proximal colonic cancers increased with advancing age in both genders. Higher proportions of poorly differentiated adenocarcinoma, mucinous carcinoma, cancer >5 cm in size, and protruding type cancer were present in the very old group, although these kinds of tumors typically occur in the proximal colon. The incidence of multiple cancers in the large intestine was not different among any age group (average, 8.6%). These results indicated that, even in the very old, colorectal cancers showed marked proximal excess, being explained by effect of both age and gender, and that the proximal shift may influence the proportion of histologic type and size of the tumor. These findings have important implications for screening and diagnosis of colorectal cancer in the elderly.

Broadsheet number 52: Molecular genetics of colorectal cancer

The molecular genetics of colorectal cancer is presented in an order that ascends from the basic to the applied: molecular mechanisms, morphogenesis, classification and diagnosis. Major consideration is given to the nature of genetic instability and the role of this mechanism in driving neoplastic progression. It is shown how the fundamental principle of genetic instability cuts across applied research, tissue diagnosis and clinical management with respect to both sporadic and inherited forms of colorectal cancer.