Joseph Knezetic

Phenotypic variation in eight extended CDKN2A germline mutation familial atypical multiple mole melanoma-pancreatic carcinoma-prone families: The familial atypical multiple mole melanoma-pancreatic carcinoma syndrome

Hereditary pancreatic carcinoma shows extant phenotypic and genotypic heterogeneity as evidenced by its integral association with a variety of hereditary cancer syndromes inclusive of the familial atypical multiple mole melanoma (FAMMM) syndrome in concert with CDKN2A (p16) germline mutations.

Microsatellite Instability and Expression of MLH1 and MSH2 in Normal and Malignant Endometrial and Ovarian Epithelium in Hereditary Nonpolyposis Colorectal Cancer Family Members

Mismatch repair deficiency is a characteristic molecular finding in hereditary nonpolyposis colorectal cancer (HNPCC), and has been demonstrated in both colorectal cancers and benign adenomas. Endometrial and ovarian cancers are common extracolonic tumors in this syndrome; however, few studies have investigated whether genetic changes occur in histologically normal endometrial and ovarian epithelia from HNPCC family members. If early genetic changes exist, they might be used as molecular markers to detect susceptibility to endometrial and ovarian cancers. In this study, we analyzed microsatellite instability (MSI) and MLH1 and MSH2 immunohistochemical expression in 20 histologically normal epithelia (12 endometrial and 8 ovarian) and 8 cancers (4 endometrial and 4 ovarian) obtained from 20 individuals representing 7 unrelated HNPCC families. While MSI was observed in endometrial (75%) and ovarian (100%) cancers, no case was determined to exhibit MSI in histologically normal epithelia of the endometrium or ovary. Similarly, in immunohistochemical expressions for MLH1 and MSH2, histologically normal epithelia had no genetic changes predisposing to malignancy. In cancer cases, a correlation existed between the expression of MLH1 and MSH2, the presence of germline mutations in the hMLH1 and hMSH2 genes, and the presence of tumor MSI. These data suggest that MSI and MLH1 and MSH2 expression are not useful biomarkers for the early detection of endometrial and ovarian malignancy in cancer-unaffected HNPCC germline mutation carriers. Further studies of other genetic changes in normal and premalignant precursor lesions are needed.

Effect of Vitamin D Receptor Genotypes on Calcium Absorption, Duodenal Vitamin D Receptor Concentration, and Serum 1,25 Dihydroxyvitamin D Levels in Normal Women

Abstract. It is well established that bone mineral density is under strong genetic control. Recently it was reported that the Bsm I restriction fragment length polymorphism of the vitamin D receptor (VDR) gene could account for up to 75% of the genetic variance in bone mineral density. However, the physiological basis for such an effect has not been established. The VDR gene codes for the vitamin D receptor protein which regulates intestinal calcium absorption. In order to assess the biochemical basis we studied the effect of common allelic variation of the VDR gene on intestinal VDR protein concentration, calcium absorption, and serum 1,25 dihydroxyvitamin D (1,25(OH)2D). Ninety-two Caucasian women were genotyped for Bsm I and Taq I polymorphism at the VDR gene locus. From these we compared 49 young women aged 25–35 years and 43 elderly women aged 65–83 years, who had all three measurements performed. There were no significant differences in intestinal VDR protein concentration, serum 1,25(OH)2D, or radioactive calcium absorption among VDR genotype groups. Therefore, the small intestine does not seem to be a target for VDR gene polymorphism.n

A century of progress in hereditary nonpolyposis colorectal cancer (lynch syndrome)

One of the earliest references to heredity in colorectal cancer dates to Aldred Warthins now-famous recollection of his seamstress distress regarding “cancer excess” in her family history. her predication of an early demise secondary to cancer of the female organs, colon, or stomach proved true. The slow, arduous investigation that ensued followed a tortuous route of nearly eight decades before the implications of such family histories were widely acknowledged through the degisnation of hereditary nonpolyposis colorectal cancer or Lynch Syndrome Variants I and II. The story of hereditary nonpolyposis colorectal cancer is one of chance meetings, the selfless sharing of information, perseverance in the face of adversity, meticulous scientific documentation, and ultimate vindication by a scientific process that yielded molecular genetic evidence through the identification of the culprit mutations (hMSH2, hMLH1, hPMS2, and hMSH6). Our purpose is to provide a brief outline of the course charted by the study of the genetics of hereditary nonpolyposis colorectal cancer. This should be of particular interest to the readers of this Journal as we celebrate 100 years of dedication to the diagnosis and treatment of diseases of the colon, rectum, and anus through the efforts of The American Society of Colon and Rectal Surgeons.

Molecular profiling of head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) exhibits high rates of recurrence, and with few approved targeted agents, novel treatments are needed. We analyzed a molecular profiling database for the distribution of biomarkers predictive of chemotherapies and targeted agents.

Renal medullary carcinomas: histopathologic phenotype associated with diverse genotypes

Chromosomal abnormalities and gene mutations have become major determinants in the classification of kidney carcinomas. Most renal medullary carcinomas develop in patients with hereditary sickle cell disease, but sporadic cases unassociated with sickle cell disease have also been described, for which underlying genetic abnormality is unknown. We evaluated 3 patients with renal medullary carcinoma (1 patient with sickle cell disease and 2 patients without sickle cell disease) for germ line and somatic mutations in genes commonly involved in pathogenesis of renal carcinomas using denaturing high-performance liquid chromatography and direct sequencing. Chromosomal abnormalities were studied by the conventional cytogenetic and SNP arrays analysis. Expression of hypoxia-inducible factor 1α was examined using immunohistochemistry. Two new mutations in the gene for fumarate hydratase were identified in 1 case of medullary renal carcinoma without sickle cell disease: a germ line mutation in exon 6 (R233H) and an acquired (somatic) mutation in exon 8 (P374S). No fumarate hydratase mutations were identified in the other 2 patients. The second sporadic case of renal medullary carcinoma harbored double somatic mutations in von Hippel-Lindau gene, and renal medullary carcinoma in the patient with sickle cell disease showed von Hippel-Lindau gene promoter methylation (epigenetic silencing). No consistent pattern of chromosomal abnormalities was found between 2 cases tested. All 3 cases showed increased hypoxia-inducible factor 1α expression. Medullary renal carcinomas from patients with or without sickle cell disease show involvement of genes important in hypoxia-induced signaling pathways. Generalized cellular hypoxia (in sickle cell disease) or pseudohypoxia (in tumors with fumarate hydratase and von Hippel-Lindau mutations or epigenetic silencing) may act alone or in concert at the level of medullary tubular epithelium to promote development of this rare type of renal carcinoma, which could then be genetically reclassified as either fumarate hydratase-associated renal carcinomas or high-grade clear cell renal cell carcinomas.

Receptors and ligands for autocrine growth pathways are up-regulated when pancreatic cancer cells are adapted to serum-free culture.

Overexpression of autocrine growth factors and their receptors has been reported in many human cancers. The study of autocrine-regulated pathways using in vitro culture systems can be hindered by the presence of fetal bovine serum in culture medium. A human pancreatic cancer cell line (HPAF) was slowly weaned from its dependence on fetal bovine serum and subsequently maintained in serum-free conditions. Growth factor secretion studies showed that production of autocrine growth factors such as transforming growth factor &agr;, gastrin-releasing peptide, and insulin-like growth factor I from weaned cells increased three times compared with nonweaned cells (p < 0.01). The epidermal growth factor and gastrin-releasing peptide receptor densities were also increased in weaned cells (2 times and 2.5 times, respectively, p < 0.05). The proliferation of weaned cells cultured continuously in the same medium was significantly greater than of nonweaned cells (p < 0.05). Collectively, these data indicate that weaned pancreatic cancer cells can proliferate in the absence of serum by up-regulating autocrine pathways.

Multiple Primary Cancer, Including Transitional Cell Carcinoma of the Upper Uroepithelial Tract in a Multigeneration HNPCC Family: Molecular Genetic, Diagnostic, and Management Implications

OBJECTIVE:We report a multigeneration family where colorectal cancer and cancer of multiple diverse anatomic sites, inclusive of transitional cell carcinoma of the upper uroepithelial tract, were manifested in several relatives.METHODS:A specific pattern of cancer of the colorectum, endometrium, ovary, small bowel, and transitional cell carcinoma, with a vertical distribution of this cancer phenotype through multiple generations, was consonant with a diagnosis of hereditary nonpolyposis colorectal cancer.RESULTS:Germline mutation testing identified the MSH2 mutation, which segregated with the cancer phenotype. This family study clearly demonstrates the value of genetic testing in the management and treatment decision process.CONCLUSIONS:We document, perhaps for the first time, how molecular genetic testing in hereditary nonpolyposis colorectal cancer can aid in the identification of a potential renal transplant donor for a relative with the MSH2 mutation who is experiencing renal insufficiency secondary to transitional cell carcinoma.

Genetics, Biomarkers, Hereditary Cancer Syndrome Diagnosis, Heterogeneity and Treatment: A Review

Opinion statementMolecular genetic pathways that drive the phenotypic and genotypic heterogeneity of hereditary colorectal cancer also can affect response to chemotherapy and chemoprevention. These mutations also can alter patients’ response to therapy. Environmental differences can affect this highly complex conundrum. We will use Lynch syndrome as a model to explore this issue. However, to begin with, after more than a century of documentation, we must ask what is meant by the eponym “Lynch syndrome”. Germline mutations may act as drivers of chemoprevention and chemotherapy and therein may act positively or conversely they may have a negative effect in terms of inhibiting the inactivation of cancer-causing germline mutations. A relatively new field of hereditary cancer therapeutics has significantly impacted cancer care, from the standpoint of the sensitivity or resistance to a particular form of chemotherapy and/or chemoprevention. The question for the diagnostician and therapist must always concern what is the best possible management approach for the patient, particularly when he or she harbors a cancer-causing germline mutation, which, in this case, causes Lynch syndrome. Continued molecular genetic research might yield a more tailored effective treatment for Lynch syndrome. The ultimate goal of such hereditary oncologic research is to better understand the mutation’s therapeutic task, namely, its potential to benefit the patient in terms of its treatment goal, thereby fulfilling the essence of personalized medicine. However, this goal may be exceedingly complicated. For example, in the natural clinical and molecular genetic history of hereditary forms of cancer, there will be a predominance of early-onset cancers of multiple anatomic sites. In our Lynch syndrome model, these will be most commonly colorectal, endometrial, and ovarian cancer. Attention must initially be focused upon cancer’s early age of onset coupled with the tendency to multiple primary cancers so that, in the case of CRC, colonoscopic screening must be initiated by age 20–25xa0years and repeated every other year until age 40xa0years and then annually thereafter. However, screening will be of limited efficacy in the gynecologic cancers (endometrial and ovarian) so that once the family is completed, particularly by age 35–40xa0years, careful attention must be given to the option of prophylactic hysterectomy and bilateral salpingo-oophorectomy. Given issues of tumor heterogeneity, selected Lynch syndrome families may show an excess of urologic cancers or cancers of the small bowel, and highly targeted screening should be given serious consideration for these as well as cancers of other anatomic sites in such high-risk, cancer-prone patients.

The role of oxygen-derived free radicals and nitric oxide in cytokine-induced antiproliferation of pancreatic cancer cells

Introduction Pancreatic cancer cells are susceptible to antiproliferative effects of cytokines such as tumor necrosis factor-alpha (TNF-&agr;). However, little is known about the mechanisms involved. Aim To determine the mechanisms of the antiproliferative effects of TNF-&agr; on pancreatic cancer cells. Methodology and Results In the current study, four of five pancreatic cancer cell lines tested were responsive to the antiproliferative effects of TNF-&agr;. In two cell lines, the effects of TNF-&agr; were completely abolished by superoxide dismutase, suggesting that superoxide anion mediates the effects. Further, inhibition of nitric oxide (NO) synthase by L-NAME potentiated the TNF-&agr; response, suggesting a protective role for endogenously produced NO in these two cell lines. MiaPaCa-2 cells, which were unresponsive to the antiproliferative effects of TNF-&agr;, produced five times more nitrite than the other cell lines. Treatment of MiaPaCa-2 cells with interferon-gamma (IFN-&ggr;) increased inducible nitric oxide synthase mRNA as shown by reverse transcription-polymerase chain reaction. This induction was potentiated by TNF-&agr; and further enhanced by a combination of three cytokines (INF-&ggr;, TNF-&agr;, and interleukin 1-beta (IL-1&bgr;). This combination of cytokines increased nitrite accumulation fourfold and inhibited the proliferation of this resistant cell line. These effects were prevented by L-NAME. Conclusions These studies suggest that TNF-&agr; inhibits proliferation of pancreatic cancer cells by increasing the production of superoxide anion and that endogenously produced NO protects against this effect. In addition, there is a direct correlation between the amount of NO produced and resistance to TNF-&agr; in the only resistant cell line. In contrast, treatment with a combination of IFN-&ggr;, TNF-&agr; and IL-1&bgr; upregulates inducible nitric oxide synthase, and the resulting markedly enhanced NO production inhibits pancreatic cancer cell growth. This pathway may provide a valuable target for therapy of this devastating disease.