Positive immunostaining for thyroid transcription factor-1 in colorectal adenocarcinoma using the 8G7G3/1 monoclonal antibody

Thyroid transcription factor-1 promotes lymph node metastasis by inducing lymphangiogenesis in ovarian carcinoma

AIMS AND BACKGROUND

Thyroid transcription factor-1 (TTF-1) expression is widely considered a specific marker for lung and thyroid carcinomas and plays an important role in angiogenesis in lung cancer. However, it can occasionally be expressed in other malignancies, including ovarian carcinomas, and the mechanism of TTF-1 in lymphatic metastasis of ovarian carcinomas is still unclear. This study aimed to define the TTF-1 expression and lymph vessel density (LVD) in ovarian carcinomas and look for their correlations with clinicopathological features.

METHODS

We examined the incidence of thyroid transcription factor 1 expression (clone SPT24) and lymph vessel density (LVD) quantified through D2-40 by immunohistochemistry from 110 primary ovarian carcinomas and 40 benign ovarian tumor as controls in Chinese patients.

RESULTS

Thyroid transcription factor 1 was detected in 28 primary ovarian carcinomas (25.5%), which was significantly higher than its expression in benign ovarian tumor. TTF-1 expression was correlated with tumor FIGO stage,T stage and lymphatic metastasis. Moreover, LVD was associated with tumor FIGO stage, TNM stage. Furthermore, the LVD counts in group of TTF-1 positive expression were higher than in group of TTF-1 negative expression.

CONCLUSIONS

These findings indicated the occasional expression of TTF-1 immunoreactivity of ovarian carcinomas should be considered in the evaluation of neoplasms of unknown primary origin and TTF-1 might be involved in lymph node metastasis of ovarian carcinomas in the presence of lymphangiogenesis.

Different cutoff values for thyroid transcription factor-1 antibodies in the diagnosis of lung adenocarcinoma

With the use of more specific treatments and targeted therapies for non-small cell lung carcinoma, distinction between adenocarcinoma (ADC) or squamous cell carcinoma (SCC) becomes increasingly important. For this, the key technique is an immunohistochemical panel in which a thyroid transcription factor-1 (TTF-1) antibody is often used. Two different TTF-1 clones (8G7G3/1 and SPT24) are used in daily practice, which appear to have different sensitivities and specificities. The aim of this study was to assess the differences between these clones and to identify the optimal cutoff value for correctly diagnosing primary or metastatic lung ADC. 182 pulmonary (109 lung ADCs, 62 lung SCCs, 11 lung metastases) and 115 extrapulmonary (36 metastatic lung ADCs, 79 nonpulmonary tumors) samples were stained with both TTF-1 antibodies. The percentage of tumor cells with nuclear staining was scored in categories of <1%, 1% to 5%, 6% to 25%, 26% to 50%, 51% to 75%, and 76% to 100%. The staining was further assessed as weak or strong. The sensitivity and specificity were calculated at different cutoff values. Applying the same cutoff value for positivity to both clones resulted in a significant difference between the clones at all cutoff values, with a lower sensitivity of 8G7G3/1 at high cutoff values and a lower specificity of SPT24 at low cutoff values. However, when the optimal cutoff value was used for each clone (>5% staining for 8G7G3/1 and >50% strong staining for SPT24), no significant difference in sensitivity (0.79 vs. 0.82) or specificity (0.98 vs. 0.98) was detected, making the clones equally useful for reliably diagnosing lung ADC.

Expression of thyroid transcription factor-1 is associated with a basal-like phenotype in breast carcinomas

Background

The differential diagnosis between primary and secondary breast cancers might be difficult, especially in poorly differentiated tumors. Thyroid Transcription Factor-1 (TTF-1) has been regarded as a reliable marker for lung or thyroid origin, with only occasional positive staining in other tumors. However, positive cases have recently been reported among primary breast carcinomas.

Methods and results

Here, we analyzed expression of TTF-1 protein (clone SPT24) by immunohistochemical staining of sections from paraffin embedded tumor samples in 247 primary breast cancers from the population-based Norwegian Breast Cancer Screening Program. Positive staining (weak or strong) was observed in 7 cases (2,8%). As novel observations, positivity was demonstrated more frequently in estrogen receptor negative cases (14,0% vs. 1,4%; p = 0,004), highly proliferative tumors (8,8% vs. 1,1%; p = 0,008), tumors with a basal-like phenotype by showing expression of CK5/6 and/or P-cadherin (11,1% vs. 1,4%; p = 0,01), and tumors with blood vessel invasion (9,7% vs. 1,9%; p = 0,04). Also, TTF-1 was associated with histological grade 3 tumors compared with grade 1 or 2 tumors (7,7% vs. 1,5%; p = 0,04) as well as lymph node positive cases (5,2% vs. 1,8%; p = 0,03).

Conclusions

Our population-based findings indicate that TTF-1 may be positive in approximately 3% of primary breast cancers, and positivity indicates an association with adverse prognostic factors.

Virtual slides

The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/8313753509421182

[TTF-1 (8G7G3/1) positive colon adenocarcinoma: diagnostic implications]

Immunohistochemical evaluation of primary and secondary (adeno-) carcinomas of the lung often includes utilisation of two different clones (8G7G3/1 or SPT24) of TTF-1 (thyroid transcription factor 1) antibodies. In a subgroup of adenocarcinomas with a primary site other than the lung a positive reaction of clone SPT24 and also of clone 8G7G3/1 is described. We report on a patient with TTF-1 (clone 8G7G3/1) positive adenocarcinoma of the colon with metastases to the eye and lung and discuss TTF-1 based diagnostic considerations.

Expression of thyroid transcription factor-1 in colorectal carcinoma

Thyroid transcription factor-1 (TTF-1) is a member of the homeodomain transcription family expressed in epithelial cells of the thyroid and lung. Although nuclear TTF-1 is generally considered a specific marker for lung and thyroid neoplasms, it has been reported to be positive in other types of tumors including colorectal carcinoma (CRC). During metastatic adenocarcinoma workup for patients who had a history of CRC, we identified 4 positive TTF-1 cases using clone 8G7G3/1. Three of the 4 corresponding primary carcinomas were also positive for TTF-1. Therefore, we sought to retrospectively investigate the expression of TTF-1 in 100 CRC cases constructed in tissue microarray blocks and whole tissue sections of the 4 primary tumors corresponding to the 4 positive metastases. In tissue microarray cases, all cases had negative nuclear staining. Our results suggest that during immunohistochemical workup for adenocarcinoma, especially when the differential diagnosis includes the lung and CRC, TTF-1 results should be interpreted with caution as a small percentage of CRC expresses this marker. Positive nuclear TTF-1 in a metastatic carcinoma does not rule out CRC primary. Clinicopathologic correlation, tumor morphology, and a panel of immunohistochemical markers are essential to render the correct diagnosis.

Comparison of thyroid transcription factor-1 expression by 2 monoclonal antibodies in pulmonary and nonpulmonary primary tumors

Thyroid transcription factor-1 (TTF-1) is a transcription factor that plays a role in the development and physiology of the thyroid and lungs. Expression of TTF-1 is used as a marker of lung and thyroid clinically. Commercially available clones of TTF-1 monoclonal antibodies, 8G7G3/1 and SPT24, have been reported to have different sensitivities for the detection of neoplasms of different origins. Although they are used extensively in daily practice, a comprehensive comparative study of these antibodies in a wide variety of neoplasms is lacking. We examined TTF-1 expression in primary tumors of the lung, prostrate, pancreas, stomach, salivary glands, breast, bladder, colon, and squamous cell carcinoma of the head and neck and compared the results obtained with both TTF-1 clones. The SPT24 clone detected more primary lung tumors of all histologic subtypes. Importantly, the SPT24 clone detected a significantly higher number of squamous cell carcinomas and carcinoid tumors of the lung. Among nonpulmonary primary tumors, a significant number of invasive urothelial carcinoma of the bladder (5.1%) was TTF-1 positive. In addition, a small proportion of prostate (1.2%), stomach (0.9%), salivary gland (1.8%), and colon (2.5%) carcinomas were positive with both clones. Of note, both clones stained the same nonpulmonary tumors with similar intensity and distribution. Carcinomas of the pancreas, breast, and squamous cell carcinomas of the head and neck were negative with both clones. In summary, the SPT24 clone detected a higher number of pulmonary non-small cell tumors of all histologic subtypes whereas both clones stained a similar proportion of nonpulmonary tumors.