Thyroid transcription factor-1 expression in colorectal adenocarcinomas

Utility of Immunohistochemistry in the Diagnosis of Pleuropulmonary and Mediastinal Cancers: A Review and Update

CONTEXT.—

Immunohistochemistry has become a valuable ancillary tool for the accurate classification of pleuropulmonary and mediastinal neoplasms necessary for therapeutic decisions and predicting prognostic outcome. Diagnostic accuracy has significantly improved because of the continuous discoveries of tumor-associated biomarkers and the development of effective immunohistochemical panels.

OBJECTIVE.—

To increase the accuracy of diagnosis and classify pleuropulmonary neoplasms through immunohistochemistry.

DATA SOURCES.—

Literature review and the author's research data and personal practice experience.

CONCLUSIONS.—

This review article highlights that appropriately selecting immunohistochemical panels enables pathologists to effectively diagnose most primary pleuropulmonary neoplasms and differentiate primary lung tumors from a variety of metastatic tumors to the lung. Knowing the utilities and pitfalls of each tumor-associated biomarker is essential to avoid potential diagnostic errors.

Recurrent Metastatic Colorectal Adenocarcinoma to the Thyroid Gland Presenting With Vocal Cord Paralysis and Inspiratory Stridor

The most common sites for metastases of colorectal cancer include the liver, lungs, brain, and regional lymph nodes. However, a limited number of reported cases describe colon cancer metastasis to the thyroid gland. Metastatic colorectal adenocarcinoma to the thyroid gland is rare. The majority of these cases with colon cancer metastases to the thyroid gland are diagnosed years after initial treatment of colon cancer. The discovery is usually made after routine surveillance imaging, and often patients have minimal or absent symptoms. We report a case of a recurrence of metastatic colorectal adenocarcinoma to the thyroid gland presenting with vocal cord paralysis and inspiratory stridor.

The Incidence of Labelling of Non-Lung Adenocarcinomas With Antibodies Against TTF-1 and Diagnostic Implications

Thyroid transcription factor 1 (TTF-1) is an immunohistochemical marker in the identification of lung and thyroid tumors. However, positive labelling for TTF-1 can occur in tumors from other sites, and this can result in misdiagnosis if only a limited panel of antibodies is used. We assessed the frequency of expression of 3 TTF-1 antibody clones, namely, 8G7G3/1, SPT24, and SP141 on a tissue microarray of 104 colorectal cancer (CRC), and whole-tumor sections of 165 CRC with known microsatellite instability (MSI) status. We also analyzed the expression of TTF-1 in a tissue microarray of 112 prostatic adenocarcinomas. The association of TTF-1 expression with clinicopathologic parameters and patient survival was analyzed. Six of 104 (5.7%) primary colorectal carcinomas expressed TTF-1 with SPT24 and SP141 clones, whereas only 2 (2%) of these tumors labeled positive for TTF-1 with clone 8G7G3/1. A significant association of TTF-1 expression with younger age at diagnosis (P=0.001) was found, but not with stage, or survival. The SP141 clone also labelled 24/165 (14.5%) of 165 CRC with known MSI status. There was an association with younger age (P<0.001), but not with MSI status or survival. TTF-1 expression was found in 39/112 (34%) prostate adenocarcinomas with 6/112 (5.3%) labelling with clone 8G7G3/1, 26/112 (23%) with clone SP141, and 31/112 (28%) with clone SPT24. TTF-1 expression appeared to be associated with extracapsular extension (P=0.022) and with higher stage (P=0.039). Here too TTF-1 expression was not associated with survival. The mRNA expression of TTF-1 in these tumors was confirmed by RTPCR, indicating that this is not false-positive labelling. Depending on the clone used, TTF-1 expression can vary with the SP141 and SPT24 clones exhibiting higher incidence of labelling. Pathologists should be aware of the differences in performance profiles of the different TTF-1 clones in diagnostic practice.

Expression of TTF-1 in breast cancer independently of ER expression: A case report and pathogenic implications

Thyroid Transcription Factor 1 (TTF-1) is often used for the immunohistochemical evaluation of lung cancers, as a significant proportion of these cancers are positive while other adenocarcinomas are usually negative. Breast cancers are known to express TTF-1 only in a small minority of cases but this may be problematic when this staining is used for its differential diagnosis from lung cancer. We present a case of ER-positive breast cancer in 30% of tumor cells that was also TTF-1 positive in some areas of the primary tumor but lost ER expression completely in the metastatic recurrence site while retaining TTF-1 positivity. Additionally, a PTEN mutation was present on genomic evaluation of the primary tumor. Diagnostic, pathogenic and therapeutic implications of these findings are discussed.

Immunohistochemistry in Diagnostic Parathyroid Pathology

Pathologists are usually readily able to diagnose parathyroid tissues and diseases, particularly when they have knowledge of the clinical information, laboratory findings, and radiographic imaging studies. However, the identification of parathyroid tissue or lesions can be difficult in small biopsies, ectopic locations, supranumerary glands, and in some oxyphil/oncocytic lesions. Widely available immunohistochemical studies such as chromogranin-A, synaptophysin, keratin, parathyroid hormone, thyroglobulin, and thyroid transcription factor-1 can help in difficult cases. One of the most difficult diagnostic aspects faced by the pathologist in evaluating parathyroid is distinguishing between parathyroid adenoma, particularly atypical adenoma, and parathyroid carcinoma. Many markers have and continue to be evaluated for diagnostic utility, and are even beginning to be studied for prognostic utility. Single immunohistochemical markers such as parafibromin and Ki-67 are among the most studied and most utilized, but many additional markers have and continue to be evaluated such as galectin-3, PGP9.5, Rb, bcl2, p27, hTERT, mdm2, and APC. Although not widely available in many laboratories, a panel of immunohistochemical markers may prove most useful as an adjunct in the evaluation of challenging parathyroid tumors.

Identifying cancer origin using circulating tumor cells

Circulating tumor cells (CTCs) have become an established clinical evaluation biomarker. CTC count provides a good correlation with the prognosis of cancer patients, but has only been used with known cancer patients, and has been unable to predict the origin of the CTCs. This study demonstrates the analysis of CTCs for the identification of their primary cancer source. Twelve mL blood samples were equally dispensed on 6 CMx chips, microfluidic chips coated with an anti-EpCAM-conjugated supported lipid bilayer, for CTC capture and isolation. Captured CTCs were eluted to an immunofluorescence (IF) staining panel consisting of 6 groups of antibodies: anti-panCK, anti-CK18, anti-CK7, anti-TTF-1, anti-CK20/anti-CDX2, and anti-PSA/anti-PSMA. Cancer cell lines of lung (H1975), colorectal (DLD-1, HCT-116), and prostate (PC3, DU145, LNCaP) were selected to establish the sensitivity and specificity for distinguishing CTCs from lung, colorectal, and prostate cancer. Spiking experiments performed in 2mL of culture medium or whole blood proved the CMx platform can enumerate cancer cells of lung, colorectal, and prostate. The IF panel was tested on blood samples from lung cancer patients (n = 3), colorectal cancer patients (n = 5), prostate cancer patients (n = 5), and healthy individuals (n = 12). Peripheral blood samples found panCK⁺ and CK18⁺ CTCs in lung, colorectal, and prostate cancers. CTCs expressing CK7⁺ or TTF-1⁺, (CK20/ CDX2)⁺, or (PSA/ PSMA)⁺ corresponded to lung, colorectal, or prostate cancer, respectively. In conclusion, we have designed an immunofluorescence staining panel to identify CTCs in peripheral blood to correctly identify cancer cell origin.

Application of Immunohistochemistry in the Diagnosis of Pulmonary and Pleural Neoplasms

CONTEXT

- A vast majority of neoplasms arising from lung or pleura are initially diagnosed based on the histologic evaluation of small transbronchial, endobronchial, or needle core biopsies. Although most diagnoses can be determined by morphology alone, immunohistochemistry can be a valuable diagnostic tool in the workup of problematic cases.

OBJECTIVE

- To provide a practical approach in the interpretation and immunohistochemical selection of lung/pleura-based neoplasms obtained from small biopsy samples.

DATA SOURCES

- A literature review of previously published articles and the personal experience of the authors were used in this review article.

CONCLUSION

- Immunohistochemistry is a useful diagnostic tool in the workup of small biopsies from the lung and pleura sampled by small biopsy techniques.

TTF-1 Expression in Rectal Adenocarcinoma: A Case Report and Review of the Literature

Thyroid transcription factor 1 (TTF-1) is considered a highly sensitive and specific marker for primary lung adenocarcinoma. However, in recent years retrospective studies of tumor samples have confirmed that, although rare, TTF-1 can also be expressed in colorectal adenocarcinoma. There are a few case reports of patients with TTF-1-positive colon adenocarcinoma in the medical literature but none of TTF-1-positive rectal adenocarcinoma. Here, we present a case of rectal adenocarcinoma with lung metastasis found to be TTF-1 positive on immunohistochemistry. A review and discussion of the available literature is also included.

[Diagnosis of brain metastases: an update in 2012]

Diagnosis of brain metastases should aim to identify anatomoclinical entities for which a specific treatment is more accurate. Growing numbers of targeted therapies have shown to be effective against specific cancers. Several studies have reported that targeted therapies are capable of reducing brain metastases in melanoma or non small cell lung cancer (NSCLC), sometimes with a high dramatic response. These results have clearly impacted routine neuropathological practice, leading to multidisciplinary strategy management of brain metastases tissues. In accordance with the recommendations of French National Cancer Institute (INCa), the pathologist develops appropriate strategies for molecular and immunohistochemical analysis, in order to provide results as soon as possible.