Guidelines for diagnosis and therapy of MEN type 1 and type 2.

This is a consensus statement from an international group, mostly of clinical endocrinologists. MEN1 and MEN2 are hereditary cancer syndromes. The commonest tumors secrete PTH or gastrin in MEN1, and calcitonin or catecholamines in MEN2. Management strategies improved after the discoveries of their genes. MEN1 has no clear syndromic variants. Tumor monitoring in MEN1 carriers includes biochemical tests yearly and imaging tests less often. Neck surgery includes subtotal or total parathyroidectomy, parathyroid cryopreservation, and thymectomy. Proton pump inhibitors or somatostatin analogs are the main management for oversecretion of entero-pancreatic hormones, except insulin. The roles for surgery of most entero-pancreatic tumors present several controversies: exclusion of most operations on gastrinomas and indications for surgery on other tumors. Each MEN1 family probably has an inactivating MEN1 germline mutation. Testing for a germline MEN1 mutation gives useful information, but rarely mandates an intervention. The most distinctive MEN2 variants are MEN2A, MEN2B, and familial medullary thyroid cancer (MTC). They vary in aggressiveness of MTC and spectrum of disturbed organs. Mortality in MEN2 is greater from MTC than from pheochromocytoma. Thyroidectomy, during childhood if possible, is the goal in all MEN2 carriers to prevent or cure MTC. Each MEN2 index case probably has an activating germline RET mutation. RET testing has replaced calcitonin testing to diagnose the MEN2 carrier state. The specific RET codon mutation correlates with the MEN2 syndromic variant, the age of onset of MTC, and the aggressiveness of MTC; consequently, that mutation should guide major management decisions, such as whether and when to perform thyroidectomy.

Loss of heterozygosity at the RET protooncogene locus in a case of multiple endocrine neoplasia type 2A.

We describe a patient affected by multiple endocrine neoplasia type 2A (MEN 2A) bearing a heterozygous germline mutation (Cys(634)Arg) in exon 11 and an additional somatic mutation of the RET protooncogene. A large intragenic deletion, spanning exon 4 to exon 16, affected the normal allele and was detected by quantitative PCR, Southern blot analysis, and screening of several polymorphic markers. This deletion causes RET loss of heterozygosity exclusively in the metastasis, thus suggesting a role for this second mutational event in tumor progression. No additional mutations were found in the other exons analyzed. We provide the first evidence that RET, a dominant oncogene, is affected by a germline mutation and by an additional somatic deletion of the wild-type allele. This unusual genetic profile may be related to the clinical course and very poor outcome.

Gemcitabine combined with continuous infusion 5-fluorouracil in advanced and symptomatic pancreatic cancer: a clinical benefit-oriented phase II study.

Gemcitabine and 5-fluorouracil are the only two compounds with reproducible activity against advanced pancreatic cancer (APC). We have evaluated a novel combination of gemcitabine and 5-fluorouracil on the clinical benefit response (CBR) end point. Eleven consecutive patients with symptomatic APC were entered in a two-stage phase II trial. Gemcitabine was administered by intravenous (i.v.) bolus injection at the dose of 1,000 mg m(-2) on days 1, 8, 15 and 5-fluorouracil 500 mg m(-2) was given by continuous i.v. infusion on days 1-5. Treatment was repeated every 28 days. A CBR was achieved in 7/11 patients. The mean time to loss of CBR was 26.5 weeks (range 14-18, median 22). Toxicity was mild and no APC patient experienced WHO grade 3 toxicity. The gemcitabine/5-fluorouracil combination is well tolerated and produces a symptomatic relief in the majority of APC patients.

Germline and somatic mutations of the RET proto-oncogene in apparently sporadic medullary thyroid carcinomas.

Medullary thyroid carcinomas (MTC) occur sporadically or as part of inherited multiple endocrine neoplasia (MEN) type 2 syndromes. To recognize misdiagnosed familial cases and to establish the frequency of somatic mutations, a series of 50 patients, clinically diagnosed with sporadic MTC, were analyzed for mutations in the RET proto-oncogene. The clinical management of the patient and of the family is different in the two cases. Germline mutations were detected in three independent cases, demonstrating that they were associated to familial MTC. The mutations affected exon 11 in two cases and exon 14 in one case. Somatic mutations were detected in eight patients (30%) and they were indicative of sporadic MTC. In seven cases the mutation affected codon 918 of exon 16 and in one case codon 634 in exon 11. No RET mutations were detected in the remaining patients. A different genetic and clinical management is proposed for individuals with a diagnosis of familial or sporadic MTC.

Seventeen-year-long follow-up of a family affected by type 2A multiple endocrine neoplasia (MEN 2A).

This paper reports the results of a 17-year-long follow-up covering 17 members of a family affected by multiple endocrine neoplasia (MEN) type 2A, first diagnosed in 1980. This family is enrolled in our screening program. The thyroid, parathyroid and adrenal glands of the family members were investigated using the most sophisticated and sensitive techniques which have become available during this period, and their DNA was genetically tested for detecting RET mutations. Thanks to the combination of these two approaches it was possible to confirm the diagnosis in the members concerned from the genetic point of view, and to achieve an early diagnosis in the young members of the last generation before the clinical onset of the disease. The detection of a RET mutation also prompted a prophylactic thyroidectomy in a four year-old boy, in a pre-tumoral stage of the disease. Lastly, evidence is provided that genetic analysis of the DNA of the chorionic villi can be carried out as a prenatal test during routine amniocentesis.

A novel point mutation in the intracellular domain of the ret protooncogene in a family with medullary thyroid carcinoma.

Specific mutations in the ret protooncogene have been found associated with multiple endocrine neoplasia type 2A (MEN 2A) and type 2B (MEN 2B) and familial medullary thyroid carcinoma (FMTC). Mutations in one of five cysteine residues in the extracellular domain have been found in over 95% of families with MEN 2A and 88% of families with FMTC. In MEN 2B patients, a specific mutation at codon 918, substituting a threonine for a methionine, has been found in 95% of cases. In FMTC, in addition to the mutations of the extracellular cysteines, three intracellular base pair changes have been reported at codons 768 and 804. Here we describe a novel intracellular mutation in exon 15 of the ret gene that leads to the substitution of an alanine for a serine at codon 891 in a family with medullary thyroid carcinoma. This amino acid change may be important in determining substrate specificity or, alternatively, may play a role in ATP binding.

Alpha-interferon induces depletion of intracellular iron content and upregulation of functional transferrin receptors on human epidermoid cancer KB cells.

We have demonstrated that interferon-alpha (IFN alpha) upregulates the epidermal growth factor receptor (EGF-R) on human epidermoid carcinoma cells. Here we report that IFN alpha induces growth inhibition and upregulation of transferrin receptor (TRF-R) on epidermoid cancer KB cells. IFN alpha does not alter TRF-R affinity for its ligand and induces a two-fold increase of TRF binding sites. IFN alpha does not modify receptor internalization and cycling. Intracellular iron levels are known to regulate TRF-R expression: we have, therefore, evaluated whether changes in the iron content could be determined by IFN alpha. Iron levels are transiently increased after addition of fresh growth medium in untreated controls but not in KB cells exposed for 48 h to IFN alpha. Iron depletion is however completely reversed 24 h later when maximal TRF-R upregulation occurs in IFN alpha-treated cells. We suggest that IFN alpha-induced iron depletion elicits a homeostatic cellular response through upregulation of TRF-R.

Evaluation of children with medullary thyroid carcinoma.

Early diagnosis and surgical treatment of medullary thyroid carcinoma (MTC) in children is essential to decrease the likelihood of metastatic spread. From 1981 to 1991, eight children under 18 years of age (five girls and three boys) with MTC were seen and seven underwent total thyroidectomy. Follow-up ranged from 14 months to 10 years after surgery. Four of the seven presented with a neck mass and elevated basal levels of calcitonin (CT). After surgery, three had recurrent disease. In the other three, the diagnosis was made after several years of screening (normal basal values of CT but increased CT levels after calcium/pentagastrin infusion). All had normal stimulated CT values postoperatively. This follow-up showed that the prognosis for MTC in children depends predominantly upon its extent at the time of the diagnosis and treatment.

Use of somatostatin analog SMS 201-995 in medullary thyroid carcinoma.

We have studied seven subjects with medullary thyroid carcinoma. Each had elevated basal serum calcitonin (CT) levels following total thyroidectomy. After subcutaneous administration of 100 micrograms of SMS 201-995, blood samples were collected at 60-minute intervals for six hours. Two patients showed a marked decrease of CT levels (patient A: baseline 565 pg/mL, nadir 150 pg/mL; patient B: baseline 1,632 pg/mL, nadir 416 pg/mL). The other five patients showed no significant change in comparison with saline infusion. Two patients were treated with SMS 201-995 (300 micrograms/day) for 90 days. One of these patients responded to the acute SMS 201-995 test and had CT levels persistently 50% lower than pretreatment values during this 90-day period. The other patient, whose CT levels did not decrease during the acute test, had persistently high values during this 90-day period but had relief of watery diarrhea even after the therapeutic trial was discontinued.

The role of radiopharmaceuticals MIBG and (V) DMSA in the diagnosis of medullary thyroid carcinoma.

The diagnostic value of 123/131I meta-iodo-benzylguanidine (MIBG) and 99mTc (V) dimercaptosuccinic acid (DMSA) was investigated in 12 patients with proven medullary thyroid carcinoma (MTC). Scintigraphic imaging with DMSA was negative in nine of 12 patients. Scintigraphy with MIBG was positive in only one case. In proven primary or recurrent disease, DMSA sensitivity was 50% and MIBG sensitivity was 25%. Such sensitivities become much lower in subjects with high calcitonin (CT) levels who have had negative surgical explorations: DMSA 17% and MIBG 0%. DMSA detected tumor in 25% of the patients and MIBG in only 8%. The positivity of these scintigraphies appears to be unrelated to carcinoembryonic antigen and CT plasma levels. Such data suggest that scintigraphies with MIBG and DMSA are only modestly useful in the diagnosis of MTC.

Preliminary report of a kindred affected from MEN IIa.

Preliminary data of a kindred with multiple endocrine neoplasia type IIa (MEN IIa) are presented. The study concerns 20 subjects belonging to 4 generations. The first is a man, previously adrenalectomized for pheochromocytoma, suffering from thyroid node with high serum calcitonin (CT) and normal tests for parathyroid function, who underwent total thyroidectomy, removal of a grossly enlarged parathyroid and subsequent autotransplantation, because the other glands seemed to be macroscopically uninvolved. In 4 further patients total thyroidectomy and removal of the parathyroid glands with autotransplantation were performed. In all patients, despite biochemical tests had disclosed parathyroid hyperfunction in only one, one or more enlarged parathyroid glands were found, subsequently diagnosed as adenomatous or with focal areas of "chief-cell" hyperplasia. In 3 out of 4 patients, a single test among those performed to detect the presence of a pheochromocytoma was positive. However, because of the lack of a clear correlation among data from biochemistry, stimulation tests and morphological investigations, adrenalectomy has not been performed. Nevertheless these patients will be closely followed up, in order to promptly state when andrenalectomy has to be performed.