Role of PTEN in gastrointestinal stromal tumor progression.
BACKGROUND
Gastrointestinal stromal tumors (GISTs) are Kit/CD117-expressing mesenchymal neoplasms of uncertain malignant potential. The lack of a reliable method of prognostication hampers the selection of patients eligible for STI571 therapy. 10q22-q23 is a region involved in chromosomal losses found in a fraction of malignant primary and metastatic GISTs harboring PTEN (phosphatase and tensin homologue deleted on chromosome 10), a tumor suppressor gene often altered in human neoplasms.


OBJECTIVE
To investigate the role of PTEN in GISTs, an issue that to our knowledge has not been addressed previously.


METHODS
PTEN status was determined in a series of 21 GISTs, with follow-up ranging between 6 and 198 months, using immunohistochemistry correlated with clinical data.


RESULTS
A greater than 25% fraction of cells with low or absent PTEN immunostaining was detected in 9 GISTs, including all those showing malignancy. By the log-rank test, a fraction of PTEN-deficient cells greater than 25% was associated with malignancy (P <.001). Percentage of cells underexpressing PTEN, size, cellularity, MIB-1 immunoreactivity, and coagulative necrosis proved to be associated with malignancy by Cox proportional hazards univariate analysis; low or absent expression of PTEN was the only factor selected by multivariate analysis (P =.03).


CONCLUSIONS
PTEN downregulation is implied in GIST progression. The immunohistochemical assessment of PTEN status appears to be a promising method of GIST prognostication.
Ricci
Riccardo
R
Department of Pathology, Università Cattolica del Sacro Cuore, Universita Cattolica, Rome, Italy. riccardoricci@rm.unicatt.it
Maggiano
Nicola
N
Castri
Federica
F
Rinelli
Alessandro
A
Murazio
Marino
M
Pacelli
Fabio
F
Potenza
Angelo Eugenio
AE
Vecchio
Fabio Maria
FM
Larocca
Luigi Maria
LM
D000368:Aged; D000369:Aged, 80 and over; D002879:Chromosomes, Human, Pair 10 / Q000235:genetics; D018450:Disease Progression; D005260:Female; D005500:Follow-Up Studies; D005770:Gastrointestinal Neoplasms / Q000737:chemistry* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D016147:Genes, Tumor Suppressor; D006801:Humans; D019394:Ki-67 Antigen / Q000032:analysis; D015993:Life Tables; D008297:Male; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000032:analysis / Q000235:genetics / Q000502:physiology*; D051059:PTEN Phosphohydrolase; D010744:Phosphoric Monoester Hydrolases / Q000032:analysis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D016016:Proportional Hazards Models; D012509:Sarcoma / Q000737:chemistry* / Q000235:genetics / Q000401:mortality / Q000473:pathology; D016019:Survival Analysis; D025521:Tumor Suppressor Proteins / Q000032:analysis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*
D019394:Ki-67 Antigen; D009363:Neoplasm Proteins; D025521:Tumor Suppressor Proteins; D010744:Phosphoric Monoester Hydrolases; D051059:PTEN Phosphohydrolase; C494929:PTEN protein, human