Expression of the alpha- and beta-subunits of human chorionic gonadotropin by subsets of parathyroid cells in states of hyperparathyroidism.
The alpha-subunit of human chorionic gonadotropin (hCG-alpha) has previously been found to be expressed in hyperplasias and tumours of numerous endocrine tissues including all those involved in MEN-I syndrome except the parathyroid glands. In the present immunohistochemical investigation of 86 patients with various states of hyperparathyroidism, expression of hCG-alpha by subsets of parathyroid cells was shown in 46 cases (54 per cent) including all states of hyperparathyroidism investigated: primary adenoma (n = 34, 44 per cent); uraemic secondary hyperplasia (n = 34, 53 per cent); MEN-I (n = 13, 77 per cent); MEN-II (n = 2, 100 per cent); and parathyroid carcinoma (n = 3, 100 per cent). Although the number of parathyroid cells expressing hCG-alpha was in general low, the occurrence of numerous immunoreactive cells appeared to be concentrated in primary adenoma and MEN-I (20 and 33 per cent of positive cases, respectively). No expression was found in ten normal control glands, except for very rare cells in one case. Expression of hCG-alpha was in part associated with that of hCG-beta, which appeared to be more commonly expressed than hCG-alpha in cases of secondary hyperparathyroidism. In separate experiments, Bouin fixation was found to preserve the immunoreactivity of hCG-alpha and hCG-beta better than the formalin fixation used in this study, suggesting that the figures may be underestimates. These immunohistochemical results are in agreement with a previous biochemical study showing hCG-alpha and hCG-beta in extracts of parathyroid tumours and extend to the parathyroid glands the otherwise ubiquitous finding of hCG-alpha expression in MEN-I-related neoplasms.
Carlinfante
G
G
Department of Anatomic Pathology, University of Parma, Italy.
Lampugnani
R
R
Azzoni
C
C
Aprile
M R
MR
Brandi
M L
ML
Bordi
C
C
D000236:Adenoma / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018997:Chorionic Gonadotropin, beta Subunit, Human / Q000378:metabolism*; D005260:Female; D015292:Glycoprotein Hormones, alpha Subunit / Q000378:metabolism*; D006801:Humans; D006961:Hyperparathyroidism / Q000378:metabolism* / Q000473:pathology; D006962:Hyperparathyroidism, Secondary / Q000378:metabolism; D007124:Immunoenzyme Techniques; D008297:Male; D008875:Middle Aged; D009377:Multiple Endocrine Neoplasia / Q000378:metabolism; D009363:Neoplasm Proteins / Q000378:metabolism; D010280:Parathyroid Glands / Q000378:metabolism*; D010282:Parathyroid Neoplasms / Q000378:metabolism; D012189:Retrospective Studies; D014511:Uremia / Q000378:metabolism
D018997:Chorionic Gonadotropin, beta Subunit, Human; D015292:Glycoprotein Hormones, alpha Subunit; D009363:Neoplasm Proteins