Microsatellite instability at selected tetranucleotide repeats is associated with p53 mutations in non-small cell lung cancer.

Microsatellite alterations are useful clonal markers for the early detection of cancer. An increase in microsatellite instability has been observed at certain tetranucleotide repeat markers (AAAGn) in lung, head and neck, and bladder cancer. However, the genetic mechanism underlying these elevated microsatellite alterations at selected tetranucleotide repeat (EMAST) tumors is still unknown. The p53 gene plays an important role in maintaining genome integrity by repairing damaged DNA. Therefore, we tested 88 non-small cell lung cancers with a panel of 13 microsatellite markers previously shown to exhibit frequent instability and also performed p53 sequence analysis in these tumors. Thirty-one of these 88 cancers (35%) demonstrated a novel allele [EMAST(+)] in > or =1 of these 13 microsatellite markers. p53 mutations were detected in 50 of 88 (57%) cancers and were significantly (P = 0.001) more common in EMAST(+) tumors (25 of 31; 81%) than in EMAST(-) tumors (25 of 57; 44%). Among squamous cell cancers, p53 mutations were detected significantly (P = 0.04) more frequently in EMAST(+) tumors (17 of 19; 89%) than in EMAST(-) tumors (10 of 18; 55%). Similarly, among primary adenocarcinomas, p53 mutations were present in 67% of the EMAST(+) tumors and in 35% of EMAST(-) adenocarcinomas. None of the 31 EMAST(+) tumors demonstrated high frequency microsatellite instability when examined with a reference panel of five mono- and dinucleotide markers. Primary lung cancers with microsatellite alterations at selected tetranucleotide repeats have a high frequency of p53 mutations and do not display a phenotype consistent with defects in mismatch repair.

Increased loss of chromosome 9p21 but not p16 inactivation in primary non-small cell lung cancer from smokers.

Epidemiological studies have demonstrated a causal association between tobacco use and carcinoma of the lung, and some genetic targets of the carcinogens in cigarette smoke have been defined recently. We further examined the effect of cigarette smoking on the frequency of allelic losses on chromosome 9p21 and the incidence of p16 inactivation. Chromosomal loss at 9p21-24 was determined by microsatellite analysis using 14 markers in 47 patients with non-small cell lung cancer. In addition, p16 gene inactivation was determined by DNA sequence analysis, methylation-specific PCR, and immunohistochemistry. Tumors from a group of nonsmokers (n = 14) were compared with tumors from a group of smokers (n = 33) matched for cell type, tumor stage, and gender. Allelic loss encompassing the p16 locus was present significantly (P = 0.01) more often in smokers (23 of 33 smokers, 70%) than in nonsmokers (4 of 14 nonsmokers, 28%). No significant differences in the frequency of p16 inactivation were observed between smokers and nonsmokers (45% versus 36%). However, homozygous deletion of the p16 gene locus and point mutation of p16 gene were only observed in tumors from smokers, whereas the p16 gene was inactivated in tumors from nonsmokers only through promoter hypermethylation. Thus, inactivation of the p16 gene is a common event in all non-small cell lung cancer, but the mechanism of gene alteration differs between smokers and nonsmokers. The significant link between tobacco and loss of the p16 locus identifies additional genetic targets of smoking in the pathogenesis of lung cancer.

Surgery in the treatment of thyroid cancer.

Patients with thyroid cancers offer a clinical challenge to the physician and surgeon for both treatment and research. It is evident that preoperative, intraoperative, and postoperative management can all favorably affect the clinical outcome. This demands close cooperation among internist, endocrinologist, radiotherapist, and surgeon. As surgeons, we advocate total thyroidectomy for most thyroid cancers, when it can be done safely, because recurrences will be minimized and the subsequent use of radioactive iodine treatment is facilitated. In the hands of an experienced thyroid surgeon, total thyroidectomy can be accomplished with a minimum of risk. In the future we hope to be able to identify patients at highest risk for aggressive tumor behavior and select these patients for the most aggressive treatment plans. In other cases early detection by surveillance of patients at risk for thyroid cancer, particularly medullary thyroid cancer, has already favorably affected prognosis by allowing treatment at an earlier stage of disease.

Defective thyrotropin receptor G-protein cyclic adenosine monophosphate signaling mechanism in the FTC human follicular thyroid cancer cell line.

BACKGROUND: Several studies report the effect of thyrotropin (thyroid-stimulating hormone [TSH]) on FTC-133) and aggressively invasive (FTC-238) clones of a human follicular thyroid cancer cell line. Specifically, TSH induces fibronectin secretion by FTC-133, possibly as a result of increased cyclic adenosine monophosphate (cAMP), yet induces in vitro invasion through a protein kinase C-dependent mechanism. In normal thyrocytes, TSH activates cAMP through a stimulatory G-protein (Gs)-linked pathway. In the FTC model we studied the effect of TSH on adenylate cyclase activation. METHODS: TSH receptor (TSH-R) mRNA was studied by reverse transcriptase polymerase chain reaction. Fibronectin transcription was analyzed by Northern blot and densitometry. cAMP levels were determined by an enzyme immunoassay. Gs alpha expression was determined by Western blot and a possible activating mutation at position 201 in Gs alpha sought by direct sequencing. RESULTS: Reverse transcriptase polymerase chain reaction confirmed the presence of TSH-R mRNA in FTC-133 and FTC-238. TSH did not increase transcription of fibronectin mRNA. FTC-133 cells exhibited higher cAMP levels than did FTC-238 cells: 30.4 +/- 8.0 versus 13.0 +/- 3.5 femtomoles/10(4) cells (mean +/- SD; p < 0.001, Mann-Whitney rank-sum test). TSH did not raise cAMP levels in either clone. Gs alpha expression is equal in both cell lines and is not increased by TSH; sequencing showed no position 201 mutations in Gs alpha. CONCLUSIONS: Prototypical TSH-Gs-cAMP signal transduction is not functional in FTC-133 or FTC-238. Our findings implicate perturbation in TSH-R.

Actin architecture of cultured human thyroid cancer cells: predictor of differentiation?

The actin cytoskeleton is important for cell structure and motility. A disordered actin architecture has been correlated with a high metastatic potential in melanoma, fibrosarcoma, and colon cancer models. Thyrotropin is known to induce growth and differentiation in cultured thyroid cells, whereas the carcinogenic phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) causes dedifferentiation and malignant transformation in many cell lines. We therefore assessed the effect of thyrotropin and TPA on the actin architecture of FTC-133 human follicular thyroid cancer cells in continuous culture. Staining of filamentous actin with rhodamine phalloidin showed that 1 mU/ml or 30 mU/ml thyrotropin-induced actin polymerization was detectable at 1 hour but more notable at 24 hours. Similarly TPA (0.008 to 10 mumol/L) caused rapid actin fiber disruption and redistribution to the cell periphery. Secondary antibody staining for alpha-actinin, a protein that binds and crosslinks actin, was more prominent after treatment with thyrotropin but decreased after TPA. These findings indicate that the actin cytoskeleton has a dynamic response to trophic factors. Thyrotropin promoted actin polymerization, but TPA caused depolymerization. These effects may correlate with cellular alpha-actinin levels. Actin architecture may therefore reflect the state of differentiation of thyroid tumor cells.

Insulinomas associated with multiple endocrine neoplasia type I: the need for a different surgical approach.

Insulinomas are usually solitary (greater than 90%) benign pancreatic tumors readily cured by enucleation or resection. To determine whether the 4% of insulinomas associated with multiple endocrine neoplasia type 1 (MEN-I) require a different surgical approach, we analyzed our experience in seven patients with MEN-I insulinomas treated during the past 28 years at the University of California, San Francisco, and 53 patients reported in the English literature. We found: (1) MEN-I insulinomas were associated with an antecedent history of other endocrinopathy or a family history of MEN-I in six of our seven patients, allowing preoperative identification of these patients. (2) All seven of our patients had hyperparathyroidism and four had pituitary tumors. Overall 83.6% of patients had hyperparathyroidism and 45.4% had pituitary tumors. (3) In our patients, MEN-I insulinomas were usually multiple (median 3; range 1 to 14). Overall, 76.3% of patients had multiple islet cell tumors. (4) Distal subtotal pancreatectomy with enucleation of any tumors identified in the head of the gland was done in five of our patients. Four are now normoglycemic and one is diabetic. Enucleation alone failed in one patient. The seventh patient was diagnosed at autopsy. Because the diagnosis of MEN-I can generally be made, preoperative strategy can address the unique pathologic features of insulinomas associated with MEN-I. The tumors are usually multiple, so local resection will fail. We recommend subtotal pancreatectomy in addition to enucleation of tumors in the head of the pancreas.

Increased plasminogen activator and type IV collagenase activity in invasive follicular thyroid carcinoma cells.

BACKGROUND: An essential difference between benign and malignant follicular thyroid tumors is the ability to invade and metastasize. Thyrotropin (TSH) stimulates invasion of cultured human follicular thyroid cancer cells (FTC-133) via a protein kinase C (PKC) dependent mechanism. Tumor invasion depends on degradation of extracellular matrix by proteases. METHODS: We analyzed protease activity in FTC-133 and its more invasive clone, FTC-238. Cells were treated with TSH or 12-0-tetradecanoyl-phorbol-13-acetate (TPA), a PKC agonist, for 24 hours. Conditioned medium and cellular extract were subjected to substrate gel zymography with either casein-plasminogen or gelatin (collagen). Western blot and immunohistochemistry confirmed protease identity. RESULTS: We found increased 50 kd urokinase-like plasminogen activator (uPA) and 62 kd gelatinase activity by FTC-238 cells compared with the less invasive FTC-133 cells. There was no effect of TSH on uPA or collagenase activity at concentrations of 0.01 to 10 mU/ml. In both FTC-133 and FTC-238, TPA incubations of 0.1 to 100 ng/ml caused a dose-dependent increase in uPA and a 94 kd type IV collagenase. CONCLUSIONS: These findings show that TSH-stimulated invasion may be due to PKC-induced activation of uPA and 94 kd type IV collagenase. uPA and basement membrane type IV collagenase warrant investigation as markers for follicular thyroid cancer.

p21WAF1 expression is associated with improved survival after adjuvant chemoradiation for pancreatic cancer.

BACKGROUND: Cell cycle arrest after DNA damage is partly mediated through the transcriptional activation of p21(WAF1) by the p53 tumor suppressor gene. p21(WAF1) and p53 are both critical in maintaining cell cycle control in response to DNA damage from radiation or chemotherapy. Therefore, we examined the role of p21(WAF1) and p53 in the determination of outcome for patients who receive radiation and/or chemotherapy for pancreatic cancer. METHODS: p21(WAF1) and p53 protein expression were determined (with the use of immunohistochemistry) in specimens from 90 patients with pancreatic cancer. Forty-four patients underwent surgical resection, and 46 patients had either locally unresectable tumors (n = 9 patients) or distant metastases (n = 37 patients). Seventy-three percent of the patients who underwent resection and 63% of the patients who did not undergo resection received radiation and/or chemotherapy. RESULTS: p21(WAF1) expression was present in 48 of 86 tumors (56%) and was significantly (P<.05) associated with advanced tumor stage. Median survival among patients with resected pancreatic cancer who received adjuvant chemoradiation with p21(WAF1)-positive tumors was significantly longer than in patients with no p21(WAF1) staining (25 vs. 11 months; P = .01). Fifty of 89 tumors (56%) stained positive for p53 protein. p53 overexpression was associated with decreased survival in patients who did not undergo resection. CONCLUSIONS: Normal p21(WAF1) expression may be necessary for a beneficial response to current adjuvant chemoradiation protocols for pancreatic cancer. Alternate strategies for adjuvant therapy should be explored for patients with pancreatic cancer who lack functional p21(WAF1).

Molecular metastases in stage I pancreatic cancer: improved survival with adjuvant chemoradiation.

BACKGROUND: Reports of improved survival rates for patients with resected adenocarcinoma of the pancreas coincide with the adoption of adjuvant chemoradiation protocols. The impact of nodal micrometastases demonstrated by molecular assays and adjuvant therapy on survival of patients with stage I pancreatic cancer has not been adequately assessed. METHODS: A retrospective analysis of postoperative chemoradiation on survival in 61 patients undergoing resection of pancreatic adenocarcinomas from 1984 to 1997 was performed. Archival tumors and regional nodes from 25 patients with stage I cancers were tested for a Kiras oncogene mutation using polymerase chain reaction and analysis for restriction fragment length polymorphisms (PCR/RFLP). RESULTS: Adjuvant chemoradiation was associated with improved survival for stage I (P < .01), but not stage III, disease. Seventeen (68%) of 25 patients with stage I disease tested had evidence of mutant Kiras in one or more regional nodes. Survival did not differ for patients with molecular micrometastases. Six of 17 (35%) patients with micrometastases received adjuvant chemoradiation and had improved survival (P < .05). CONCLUSIONS: The majority of patients with stage I pancreatic cancer have PCR/RFLP evidence of lymph node micrometastases. Adjuvant chemoradiation improves survival in these patients by treating micrometastases not detected by histology. Adjuvant chemoradiation should be used for patients with stage I pancreatic cancers.

Results of surgical treatment for hyperparathyroidism associated with renal disease.

Recently, the role and timing of surgery for treating secondary and tertiary hyperparathyroidism (HPT) have been questioned. In order to delineate the indications for surgery in these patients, a retrospective analysis of 53 consecutive patients treated with parathyroidectomy was conducted. Subtotal thyroidectomy was done in 37 of 45 patients undergoing their initial operations for HPT. Eight additional patients were referred after failed operations. Of 33 patients with preoperative bone pain, 70% improved. Joint pain improved in 87% of 30 patients, pruritus improved in 81% of 27 patients, and preoperative malaise improved in 73% of 33 patients after parathyroidectomy. Abdominal pain and irritated eyes were unlikely to improve. The best predictors of a successful outcome were a markedly elevated preoperative immunoreactive parathyroid hormone (mid-region) level and an elevated alkaline phosphatase level. There were no perioperative deaths. One patient (1.6%) had a recurrent laryngeal nerve injury, and one patient required reoperation for a neck hematoma. No patient had permanent hypoparathyroidism, but transient hypocalcemia (less than 7 mg/dL) occurred in 22%. Postoperative hypocalcemia correlated with elevated preoperative alkaline phosphatase levels (r2 = 0.247).

Indications for parathyroidectomy and extent of treatment for patients with secondary hyperparathyroidism.

Some manifestations of secondary hyperparathyroidism affect most if not all patients with chronic renal failure and can affect many different organ systems. Proper medical treatment is essential and should be attempted before considering surgical intervention. The symptoms that most often resolve after parathyroidectomy include bone pain and intractable pruritus. Other useful indications for operation include a marked elevation of the parathyroid hormone level and the elevation of the calcium x phosphate product over 70. Both subtotal parathyroidectomy and total parathyroidectomy with autotransplantation have been advocated as the best operative approach. Each of these procedures has its own advantages and disadvantages which should be considered for each individual case. Localizing procedures should be reserved for patients with persistent or recurrent hyperparathyroidism, as diffuse parathyroid hyperplasia is the most common operative finding in secondary hyperparathyroidism.

Functioning and nonfunctioning adrenocortical carcinoma: clinical presentation and therapeutic strategies.

Adrenocortical cancers are relatively rare endocrine tumors that usually present when hormonally active or after they have become large and metastasis has occurred. Consequently, the 5-year survival rate is 20% to 35%. Surgical removal remains the only form of therapy proven to prolong survival. Mitotane is the most accepted form of chemotherapy. For the approximately 20% to 25% of patients whose tumors respond to mitotane, survival is prolonged.

Large lymphangioma of the adrenal gland: case report.

OBJECTIVE: To characterize adrenal lymphangiomas and discuss management strategies based on findings. METHODS: We present a case report and review the pertinent literature. RESULTS: In a 35-year-old man with painless hematuria for several days, a computed tomographic (CT) scan of the abdomen disclosed an 8-cm right adrenal mass. It had the appearance of a loculated cyst with several septations. The histologic diagnosis of the excised lesion was lymphangioma with cystic degeneration. The most frequently occurring cystic adrenal masses are endothelial lesions. Lymphangiomas of the adrenal gland have a characteristic mutiloculated appearance on ultrasonography and CT. Small asymptomatic smooth adrenal cysts with clear fluid can simply be observed, whereas large symptomatic adrenal lymphangiomas should be excised. CONCLUSION: The preferred studies for detection of adrenal lymphangiomas are CT and ultrasonography. The size of the lesion, type of cystic fluid, symptomatic status, and cytologic findings dictate management options.

Acute extracapsular parathyroid hemorrhage: case report and review of the literature.

OBJECTIVE: To describe a patient with extracapsular parathyroid hemorrhage and review the signs and symptoms of this condition. METHODS: We report a case of extracapsular parathyroid hemorrhage in a patient with primary hyperparathyroidism and present an overview of previously reported cases. RESULTS: A 48-year-old woman with documented primary hyperparathyroidism, who was awaiting surgical intervention, had acute onset of a neck mass, neck pain, and dysphagia. She was found to have sustained a spontaneous extracapsular hemorrhage of a parathyroid adenoma. Hypercalcemia persisted, and she subsequently underwent curative parathyroidectomy for the primary hyperparathyroidism. We also identified 15 previously reported cases of extracapsular parathyroid hemorrhage and summarized the most common manifestations-most notably, a neck mass or swelling, ecchymoses of the neck and chest, dysphagia, neck pain, hoarseness, and dyspnea. CONCLUSION: Clinicians should be aware of the potential for occurrence of extracapsular parathyroid hemorrhage in patients with primary hyperparathyroidism. When this condition occurs, severe hypercalcemia or acute hypocalcemia may be present. Hypercalcemia is often persistent; however, autoinfarction of the parathyroid adenoma is possible.

Elevated calcium level in parathyroid cyst fluid.

Parathyroid cysts are uncommon neck masses. The diagnosis is generally established when the parathormone level is found to be elevated in the typically clear cyst fluid obtained by fine needle aspiration. We present a case where the serum and cyst fluid intact parathormone levels were normal yet the diagnosis was established by demonstrating an elevated fluid calcium level. The cyst recurred after two attempts at aspiration, so the patient underwent a curative operative excision.

Laparoscopic removal of a right adrenal pheochromocytoma in a pregnant woman.

Pheochromocytomas are a rare cause of hypertension in pregnancy. Laparoscopic adrenalectomy has been used effectively and safely in nonpregnant patients with pheochromocytoma, with the resultant benefits to the patients of less postoperative pain, shorter hospital stay, and quicker return to normal activities than is associated with open techniques. This represents the first report of a laparoscopic adrenalectomy for pheochromocytoma in a pregnant woman. Issues that are unique to laparoscopic surgery in pregnant patients are discussed.

Early experience with laparoscopic splenectomy.

BACKGROUND: Laparoscopic splenectomy is an example of the recent continued advancement in laparoscopic surgery as techniques are adapted for procedures previously done only via a laparotomy. METHODS: We analyzed our initial experience with laparoscopic splenectomy for details of the operative procedure and the clinical outcome including length of stay and complication rates. RESULTS: Two surgeons performed 11 laparoscopic splenectomies for cancer or hematologic disorders. In two instances (18%) conversion to open splenectomy was necessary due to bleeding at the splenic hilum. There were no mortalities. Two patients developed pancreatic fluid collections that were successfully drained percutaneously. The seven patients who had an uncomplicated course resumed eating a regular diet in 2.0 +/- 0.6 days (mu +/- SD) and had a hospital stay of 2.7 +/- 1.1 days. Hospital stay was significantly longer for the patients who had complications 9.7 +/- 7.2 days (p < 0.05) and for the 11 patients undergoing on elective uncomplicated open splenectomy during the same time period, 6.5 +/- 2.0 days (p < 0.05). For the 9 patients who had a completed laparoscopic splenectomy, the mean operative blood loss was 263.9 +/- 241.4 cc. The mean operative time was 293.3 +/- 91.4 minutes. The spleens removed laparoscopically weighed an average of 390 grams (range 17 to 1584 grams). CONCLUSIONS: Laparoscopic splenectomy can be performed safely and is associated with a rapid resumption of oral alimentation and shortened hospital stay compared to open splenectomy. Complications experienced in our early experience included conversion to open splenectomy and fluid collections from pancreatic leakage.

Physiology of the APUD system.

The characteristic biochemical pathway of the APUDoma cell, namely amine precursor uptake and decarboxylation, are illustrated by the examples of serotonin and catecholamine metabolism. Increasing understanding of the origins of APUDomas as well as the biochemistry and physiology of the hormones they produce, has led to improved methods of detection, imaging and treatment of afflicted patients.