Sources/Clones
Calbiochem (212-10.7). Polyclonal antibodies raised in rabbits and sheep: PTHRP (1-34), PTHRP (50-69) and PTHRP (106-141) (Danks et al, 1990); PTHRP (1-130) (Druker and Campos, Toronto, Canada).
Fixation/Preparation
Applicable to both frozen sections and formalin-fixed, paraffin-embedded tissue sections.
Background
Humoral hypercalcemia of malignancy (HHM) is a syndrome characterized by low levels of PTH, few/absent bone metastases and hypophosphatemia. Parathyroid hormone-related protein (PTHrP) has been isolated from tumors with HHM and shown to be responsible for the PTH-like effects and disruption of calcium homeostasis (Ralston et al, 1991; Roskams & Desmet, 1997) The amino acid sequence of PTHrP bears homology to PTH from amino acid 1-13, but is unique thereafter (Burtis et al, 1990). Although functioning via PTH receptor, PTHrP is the product of a separate gene located on the short arm of chromosome 12 (Suva et al, 1987). Antibody to PTHrP (Ab-1) reacts with amino acid residues 38-64 of human PTHrP and shows no crossreactivity with human parathyroid hormone.
In addition to being produced by malignant tumors, PTHrP is found in normal keratinocytes, lactating mammary tissue, placenta, parathyroid glands, the central nervous system and a number of other sites, suggesting that it may have a widespread physiologic role (Burtis et al, 1990; Kramer et al, 1991). PTHrP is thought to act in an autocrine and paracrine manner in various tissues to modulate other functions in addition to regulating calcium mobilization.
Immunostaining for PTHrP suggests that production of the peptide by stromal cells and giant cells may be involved in the formation of osteoclast-like cells in giant cell tumor of tendon sheath by acting in an autocrine/paracrine fashion (Nakashima et al, 1996).
Applications
Most squamous cell carcinomas from a variety of sites synthesize PTHrP irrespective of the calcium status of the patient (Lloyd, 1994). Using a polyclonal antibody to PTHrP (1-130), 93% of 40 invasive squamous cell carcinomas were found to be immunopositive (Liapis et al, 1993). Interestingly, the strongest immunoreactivity for PTHrP in the squamous carcinomas was in areas of invasion and with desmoplasia. Adenocarcinomas (smaller percentage than squamous cancers) of breast, lung and kidney, hepatocellular carcinoma, mesothelioma, neuroendocrine tumors and T-cell leukemias are other neoplasms that may express PTHrP (Lloyd, 1994). A recent study demonstrated the presence of PTHrP and its receptor in normal breast epithelium and breast carcinomas, demonstrating that most breast tumors are able to respond to PTHrP (Downey et al, 1997).
A recent study has shown cholangiocarcinomas to be immunopositive for PTHrP (and chromogranin A), whilst all hepatocellular carcinomas were negative (Roskams et al, 1993). Mixed primary liver tumors contained PTHrP immunoreactivity only in areas of cholangiocellular differentiation. Moreover, all metastatic adenocarcinomas (especially from GIT) were negative except for 2/5 metastatic breast carcinomas.
Using polyclonal antibodies against synthetic PTHrP peptides, immunopositivity was demonstrated in primary parathyroid adenomata and hyperplastic glands from patients with chronic renal failure, whilst primary hyperplastic glands were negative (Danks et al, 1990).
Comments
The frequency of expression of PTHrP is so great and widespread that it may be useful as a tumor marker in the histological diagnosis of certain cancers, e.g. squamous cell carcinoma of the lung. Furthermore, the role of PTHrP in distinguishing between primary hepatocellular carcinoma and cholangiocarcinoma in the liver appears to be fairly reliable. Reactive bile ductules or squamous epithelium of epidermis are recommended control tissues.
References
•Burtis WJ, Brady TG, Orloff JJ et al 1990. Immunochemical characterization of circulating parathyroid hormone-related protein in patients with humoral hypercalcemia of cancer. New England Journal of Medicine 322: 1106-1112.
•Danks JA, Ebeling PR, Hayman JA et al 1990. Immunohistochemical localization of parathyroid hormone-related protein in parathyroid adenoma and hyperplasia. Journal of Pathology 161: 27-33.
•Downey SE, Hoyland J, Freemont AJ et al 1997. Expression of the receptor for parathyroid hormone-related protein in normal and malignant breast tissue. Journal of Pathology 183: 212-217.
•Kramer S, Reynolds FH Jr, Castillo M et al 1991. Immunological identification and distribution of parathyroid hormone-like protein polypeptides in normal and malignant tissues. Endocrinology 128: 1927-1937.
•Liapis H, Crouch EC, Roby J, Rader JS 1993. In situ localization of parathyroid hormone-like protein and Mrna in intraepithelial neoplasia and invasive carcinoma of the uterine cervix. Human Pathology 24: 1058-1066.
•Lloyd RV 1994. Parathyroid hormone-related protein: role in hypercalcemia of malignancy. Advances in Anatomic Pathology 1: 82-86.
•Nakashima M, Ito M, Ohtsuru A et al 1996. Expression of parathyroid hormone (PTH)-related peptide (PTHrP) and PTH/PTHrP receptor in giant cell tumour of tendon sheath. Journal of Pathology 180: 80-84.
•Ralston SH, Danks J, Hayman J et al 1991. Parathyroid hormone-related protein of malignancy: immunohistochemical and biochemical studies in normocalcaemic and hypercalcaemic patients with cancer. Journal of Clinical Pathology 44: 472-476.
•Roskams T, Desmet V 1997. Parathyroid-hormone-related peptides. A new class of multifunctional proteins. American Journal of Pathology 150: 779-785.
•Roskams T, Willems M, Campos RV et al 1993. Parathyroid hormone-related peptide expression in primary and metastatic liver tumours. Histopathology 23: 519-525.
•Suva LJ, Winslow GA, Wettenhall REH et al 1987. A parathyroid hormone-related protein implicated in malignant hypercalcemia: cloning and expression. Science 237: 893-896.
Bibliografia
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
Calbiochem (212-10.7). Polyclonal antibodies raised in rabbits and sheep: PTHRP (1-34), PTHRP (50-69) and PTHRP (106-141) (Danks et al, 1990); PTHRP (1-130) (Druker and Campos, Toronto, Canada).
Fixation/Preparation
Applicable to both frozen sections and formalin-fixed, paraffin-embedded tissue sections.
Background
Humoral hypercalcemia of malignancy (HHM) is a syndrome characterized by low levels of PTH, few/absent bone metastases and hypophosphatemia. Parathyroid hormone-related protein (PTHrP) has been isolated from tumors with HHM and shown to be responsible for the PTH-like effects and disruption of calcium homeostasis (Ralston et al, 1991; Roskams & Desmet, 1997) The amino acid sequence of PTHrP bears homology to PTH from amino acid 1-13, but is unique thereafter (Burtis et al, 1990). Although functioning via PTH receptor, PTHrP is the product of a separate gene located on the short arm of chromosome 12 (Suva et al, 1987). Antibody to PTHrP (Ab-1) reacts with amino acid residues 38-64 of human PTHrP and shows no crossreactivity with human parathyroid hormone.
In addition to being produced by malignant tumors, PTHrP is found in normal keratinocytes, lactating mammary tissue, placenta, parathyroid glands, the central nervous system and a number of other sites, suggesting that it may have a widespread physiologic role (Burtis et al, 1990; Kramer et al, 1991). PTHrP is thought to act in an autocrine and paracrine manner in various tissues to modulate other functions in addition to regulating calcium mobilization.
Immunostaining for PTHrP suggests that production of the peptide by stromal cells and giant cells may be involved in the formation of osteoclast-like cells in giant cell tumor of tendon sheath by acting in an autocrine/paracrine fashion (Nakashima et al, 1996).
Applications
Most squamous cell carcinomas from a variety of sites synthesize PTHrP irrespective of the calcium status of the patient (Lloyd, 1994). Using a polyclonal antibody to PTHrP (1-130), 93% of 40 invasive squamous cell carcinomas were found to be immunopositive (Liapis et al, 1993). Interestingly, the strongest immunoreactivity for PTHrP in the squamous carcinomas was in areas of invasion and with desmoplasia. Adenocarcinomas (smaller percentage than squamous cancers) of breast, lung and kidney, hepatocellular carcinoma, mesothelioma, neuroendocrine tumors and T-cell leukemias are other neoplasms that may express PTHrP (Lloyd, 1994). A recent study demonstrated the presence of PTHrP and its receptor in normal breast epithelium and breast carcinomas, demonstrating that most breast tumors are able to respond to PTHrP (Downey et al, 1997).
A recent study has shown cholangiocarcinomas to be immunopositive for PTHrP (and chromogranin A), whilst all hepatocellular carcinomas were negative (Roskams et al, 1993). Mixed primary liver tumors contained PTHrP immunoreactivity only in areas of cholangiocellular differentiation. Moreover, all metastatic adenocarcinomas (especially from GIT) were negative except for 2/5 metastatic breast carcinomas.
Using polyclonal antibodies against synthetic PTHrP peptides, immunopositivity was demonstrated in primary parathyroid adenomata and hyperplastic glands from patients with chronic renal failure, whilst primary hyperplastic glands were negative (Danks et al, 1990).
Comments
The frequency of expression of PTHrP is so great and widespread that it may be useful as a tumor marker in the histological diagnosis of certain cancers, e.g. squamous cell carcinoma of the lung. Furthermore, the role of PTHrP in distinguishing between primary hepatocellular carcinoma and cholangiocarcinoma in the liver appears to be fairly reliable. Reactive bile ductules or squamous epithelium of epidermis are recommended control tissues.
References
•Burtis WJ, Brady TG, Orloff JJ et al 1990. Immunochemical characterization of circulating parathyroid hormone-related protein in patients with humoral hypercalcemia of cancer. New England Journal of Medicine 322: 1106-1112.
•Danks JA, Ebeling PR, Hayman JA et al 1990. Immunohistochemical localization of parathyroid hormone-related protein in parathyroid adenoma and hyperplasia. Journal of Pathology 161: 27-33.
•Downey SE, Hoyland J, Freemont AJ et al 1997. Expression of the receptor for parathyroid hormone-related protein in normal and malignant breast tissue. Journal of Pathology 183: 212-217.
•Kramer S, Reynolds FH Jr, Castillo M et al 1991. Immunological identification and distribution of parathyroid hormone-like protein polypeptides in normal and malignant tissues. Endocrinology 128: 1927-1937.
•Liapis H, Crouch EC, Roby J, Rader JS 1993. In situ localization of parathyroid hormone-like protein and Mrna in intraepithelial neoplasia and invasive carcinoma of the uterine cervix. Human Pathology 24: 1058-1066.
•Lloyd RV 1994. Parathyroid hormone-related protein: role in hypercalcemia of malignancy. Advances in Anatomic Pathology 1: 82-86.
•Nakashima M, Ito M, Ohtsuru A et al 1996. Expression of parathyroid hormone (PTH)-related peptide (PTHrP) and PTH/PTHrP receptor in giant cell tumour of tendon sheath. Journal of Pathology 180: 80-84.
•Ralston SH, Danks J, Hayman J et al 1991. Parathyroid hormone-related protein of malignancy: immunohistochemical and biochemical studies in normocalcaemic and hypercalcaemic patients with cancer. Journal of Clinical Pathology 44: 472-476.
•Roskams T, Desmet V 1997. Parathyroid-hormone-related peptides. A new class of multifunctional proteins. American Journal of Pathology 150: 779-785.
•Roskams T, Willems M, Campos RV et al 1993. Parathyroid hormone-related peptide expression in primary and metastatic liver tumours. Histopathology 23: 519-525.
•Suva LJ, Winslow GA, Wettenhall REH et al 1987. A parathyroid hormone-related protein implicated in malignant hypercalcemia: cloning and expression. Science 237: 893-896.
Bibliografia
Manual of diagnostic antibodies for immunohistology / Anthony S.-Y. Leong, Kumarasen Cooper, F. Joel W.-M. Leong.
