Expansion of a cell population expressing stem cell markers in parathyroid glands from patients with hyperparathyroidism.
OBJECTIVE
We sought to examine abnormal parathyroid glands for the presence of stem cells.


BACKGROUND
Cancer stem cells have been identified in cancers from a variety of tissues as a CD44/CD24 cell population. We hypothesize that stem cells (SC) may also be involved in the pathogenesis of benign clonal expansion characteristic of hyperparathyroidism (HPT).


METHODS
Under institutional review board approval, parathyroid tissue was obtained from 20 patients with HPT and analyzed by fluorescence-activated cell sorting (FACS) for the CD44/CD24 cell population. Immunohistochemistry (IHC) with CD44 antibody was correlated with FACS results.


RESULTS
Parathyroid tissue was obtained for FACS analysis from 25 enlarged parathyroid glands from 20 patients, 17 with primary HPT, and 3 with secondary HPT. The average percent of SC defined as CD44/CD24 population was 10.93% for enlarged parathyroid glands. IHC using CD44 antibody was performed on 27 abnormal parathyroid glands and 7 normal parathyroid gland biopsies from the same patients. Although IHC was not as sensitive as FACS, comparison of IHC and FACS results for 24 abnormal glands gave a correlation coefficient of 0.52, which was statistically significant (P = 0.01, Spearman rank). By IHC, 13 of 27 abnormal glands stained 1+ to 3+ (average, 0.93) compared with no CD44 staining in normal glands, which was statistically different (mean IHC of 0 vs. 0.93, P = 0.03, Wilcoxon).


CONCLUSIONS
These novel findings demonstrate expansion of a resident cell population that expresses SC markers in abnormal parathyroid glands from patients with HPT. Our results suggest that clonal expansion of a resident SC population occurs in the pathogenesis not only of cancer, but also in benign parathyroid tumors occurring in HPT.
Fang
Sandy H
SH
Department of Surgery, University of Iowa, Iowa City, IA 52242, USA.
Guidroz
Julie A
JA
O'Malley
Yunxia
Y
Lal
Geeta
G
Sugg
Sonia L
SL
Howe
James R
JR
Jensen
Chris S
CS
Weigel
Ronald J
RJ
D051927:CD24 Antigen / Q000032:analysis; D005434:Flow Cytometry; D006801:Humans; D018960:Hyaluronan Receptors / Q000032:analysis; D006961:Hyperparathyroidism / Q000473:pathology*; D007150:Immunohistochemistry; D010280:Parathyroid Glands / Q000473:pathology*; D013234:Stem Cells / Q000276:immunology / Q000473:pathology*
D051927:CD24 Antigen; D018960:Hyaluronan Receptors