Diagnostic value of tumor M2-pyruvate kinase in neuroendocrine tumors. A comparative study with chromogranin A.
OBJECTIVE
M2-pyruvate kinase isoenzyme (M2-PK) is expressed by undifferentiated or proliferating tissue. The aim of the study was to establish the diagnostic role of tumor M2-PK (TM2-PK) in patients with neuroendocrine tumors and to compare its diagnostic value with that of chromogranin A (CgA) which is well-established.


METHODS
Forty-nine patients with proven neuroendocrine tumors were divided as follows: subgroup A (17 patients in whom the tumor was surgically removed), subgroup B (9 patients with the neoplasm without metastases) and subgroup C (23 patients with tumor and distant metastases). Twenty-four healthy subjects were also studied as controls. Plasma TM2-PK and CgA were measured using ELISA techniques.


RESULTS
TM2-PK concentrations (cut-off value 5.6 U/mL) were abnormally high in 25.0% of the healthy subjects, in 41.2% of the patients of subgroup A, in 66.7% of those of subgroup B and in 78.3% of those of subgroup C. CgA concentrations (cut-off value 5.0 U/L) were normal in all healthy subjects, whereas they were abnormally high in 76.5% of the patients of subgroup A, in 88.9% of those of subgroup B and in 95.7% of those of subgroup C.


CONCLUSIONS
Since TM2-PK has a sensitivity similar to that of CgA while its specificity is significantly lower (p = 0.031), it seems of limited value in detecting neuroendocrine tumors.
Pezzilli
Raffaele
R
Department of Internal Medicine and Gastroenterology, Sant'Orsola-M. Malpighi Hospital, University of Bologna, Italy. pezzilli@orsola-malpighi.med.unibo.it
Migliori
Marina
M
Morselli-Labate
Antonio Maria
AM
Campana
Davide
D
Ventrucci
Maurizio
M
Tomassetti
Paola
P
Corinaldesi
Roberto
R
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood*; D053379:Chromogranin A; D002864:Chromogranins / Q000097:blood*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D018358:Neuroendocrine Tumors / Q000097:blood* / Q000201:enzymology* / Q000473:pathology; D011770:Pyruvate Kinase / Q000097:blood*
D014408:Biomarkers, Tumor; C506150:CHGA protein, human; D053379:Chromogranin A; D002864:Chromogranins; D011770:Pyruvate Kinase