Fig. 1Representative histologic features and immunohistochemical findings for phosphatase and tensin homolog on chromosome ten (PTEN) of typical carcinoid (TC) and large cell neuroendocrine carcinoma (LCNEC). A TC (A) shows positive expression of PTEN (B), whereas a LCNEC (C) shows loss of PTEN expression (D).
Fig. 2Comparison of the frequency of phosphatase and tensin homolog on chromosome ten (PTEN) expression with histologic subtypes of 75 pulmonary neuroendocrine (NE) tumors. The frequency of loss of PTEN expression was different between the histologic subtypes of pulmonary NE tumors (p=.025). In pairwise comparison, the frequency of loss of PTEN expression was significantly different between typical carcinoids (TCs) and large cell neuroendocrine carcinomas (LCNECs) (p<.001). AC, atypical carcinoid; SCLC, small cell lung carcinoma.
Fig. 3Comparison of mean normalized Ct (ΔCt) values of microRNA-21 (miR-21) with histologic subtypes of 75 pulmonary neuroendocrine (NE) tumors. The expression level of miR-21 was clearly different between the histologic subtypes of pulmonary NE tumors (p<.001). In pairwise comparison, the expression level of miR-21 was significantly higher in large cell neuroendocrine carcinoma (LCNEC) than in typical carcinoid (TC) (p<.001), in small cell lung carcinoma (SCLC) than in TC (p<.001), and in LCNEC than in atypical carcinoid (AC) (p=.037).
Table 1.Differential expressions of PTEN and miR-21 according to the histologic subtypes of 75 pulmonary neuroendocrine tumors
Histologic subtype |
Loss of PTEN expression (%) |
p-value |
Normalized Ct value of miR-21 (mean ± standard deviation) |
p-value |
TC (n = 23) |
4 (17.4) |
.025 |
–4.13 ± 1.67 |
< .001 |
AC (n = 9) |
4 (44.4) |
|
–4.66 ± 1.39 |
|
LCNEC (n = 22) |
16 (72.7) |
|
–6.35 ± 1.30 |
|
SCLC (n = 21) |
9 (42.9) |
|
–6.12 ± 1.27 |
|
Table 2.Correlation between PTEN expression and normalized Ct values of miR-21 in 75 pulmonary neuroendocrine tumors
Histologic subtype |
Normalized Ct value of miR-21 (mean ± standard deviation)
|
p-value |
Loss of PTEN expression |
Positive PTEN expression |
Total (n = 75) |
–6.11 ± 1.52 |
–4.81 ± 1.62 |
< .001 |
TC (n = 23) |
–4.53 ± 0.14 |
–3.36 ± 1.73 |
.014 |
AC (n = 9) |
–5.32 ± 0.13 |
–4.47 ± 1.55 |
.487 |
LCNEC (n = 22) |
–7.16 ± 0.89 |
–5.48 ± 1.22 |
.005 |
SCLC (n = 21) |
–6.97 ± 1.14 |
–5.86 ± 1.22 |
.086 |